यदि \(a_n=5n^2-3n+2\) है, तो \(a_4\) का मान क्या होगा?
If \(a_n=5n^2-3n+2\), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (66)
B (68)
C (70)
D (72)
Explanation opens after your attempt
Step 1
Concept
\(a_4=5\times16-12+2=70\). In exams, handle the square part and subtraction separately.
Step 2
Why this answer is correct
The correct answer is C. (70). \(a_4=5\times16-12+2=70\). In exams, handle the square part and subtraction separately.
Step 3
Exam Tip
\(a_4=5\times16-12+2=70\) है। परीक्षा में वर्ग वाला भाग और घटाव अलग-अलग करें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(7,24,51,88,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(7,24,51,88,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=5n^2+2n\)
B \(a_n=7n\)
C \(a_n=3n^2+4n\)
D \(a_n=17n-10\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=5n^2+2n\)
Step 1
Concept
Using \(5n^2+2n\) gives the given terms. In exams, substitute (n=1,2,3) to match options.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=5n^2+2n\). Using \(5n^2+2n\) gives the given terms. In exams, substitute (n=1,2,3) to match options.
Step 3
Exam Tip
\(5n^2+2n\) रखने पर दिए पद मिलते हैं। परीक्षा में (n=1,2,3) रखकर विकल्प मिलाएँ।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=3n^2+4n-5\) है, तो \(a_6\) का मान क्या होगा?
If \(a_n=3n^2+4n-5\), what is the value of \(a_6\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (119)
B (123)
C (127)
D (131)
Explanation opens after your attempt
Step 1
Concept
\(a_6=3\times36+24-5=127\). In exams, write positive and negative terms separately.
Step 2
Why this answer is correct
The correct answer is C. (127). \(a_6=3\times36+24-5=127\). In exams, write positive and negative terms separately.
Step 3
Exam Tip
\(a_6=3\times36+24-5=127\) है। परीक्षा में धन और ऋण पदों को अलग लिखें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,11,26,47,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(2,11,26,47,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=2n^2\)
B \(a_n=3n^2-1\)
C \(a_n=n^2+8n-7\)
D \(a_n=9n-7\)
Explanation opens after your attempt
Correct Answer
B. \(a_n=3n^2-1\)
Step 1
Concept
\(3n^2-1\) gives (2,11,26,47). In exams, identify a quadratic rule from second differences.
Step 2
Why this answer is correct
The correct answer is B. \(a_n=3n^2-1\). \(3n^2-1\) gives (2,11,26,47). In exams, identify a quadratic rule from second differences.
Step 3
Exam Tip
\(3n^2-1\) से (2,11,26,47) मिलते हैं। परीक्षा में दूसरे अंतर देखकर वर्गीय नियम पहचानें।
Login to save your score, XP, coins and progress. Login
यदि (a_n=\frac{n(4n+1)}{2}) है, तो \(a_5\) का मान क्या होगा?
If (a_n=\frac{n(4n+1)}{2}), what is the value of \(a_5\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(\frac{95}{2}\)
B \(\frac{101}{2}\)
C \(\frac{105}{2}\)
D \(\frac{111}{2}\)
Explanation opens after your attempt
Correct Answer
C. \(\frac{105}{2}\)
Step 1
Concept
\(a_5=\frac{5\times21}{2}=\frac{105}{2}\). In exams, find the bracket value first.
Step 2
Why this answer is correct
The correct answer is C. \(\frac{105}{2}\). \(a_5=\frac{5\times21}{2}=\frac{105}{2}\). In exams, find the bracket value first.
Step 3
Exam Tip
\(a_5=\frac{5\times21}{2}=\frac{105}{2}\) है। परीक्षा में पहले कोष्ठक का मान निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(\frac{5}{2},9,\frac{39}{2},34,\ldots\) के लिए सही सामान्य पद कौन-सा है?
Which general term is correct for the sequence \(\frac{5}{2},9,\frac{39}{2},34,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (a_n=\frac{n(4n+1)}{2})
B (a_n=\frac{n(n+4)}{2})
C \(a_n=4n-1\)
D \(a_n=\frac{3n^2+n}{2}\)
Explanation opens after your attempt
Correct Answer
A. (a_n=\frac{n(4n+1)}{2})
Step 1
Concept
(\frac{n(4n+1)}{2}) gives the given terms. In exams, test fractional terms with small (n).
Step 2
Why this answer is correct
The correct answer is A. (a_n=\frac{n(4n+1)}{2}). (\frac{n(4n+1)}{2}) gives the given terms. In exams, test fractional terms with small (n).
Step 3
Exam Tip
(\frac{n(4n+1)}{2}) से दिए पद मिलते हैं। परीक्षा में भिन्न पदों को भी छोटे (n) से जाँचें।
Login to save your score, XP, coins and progress. Login
यदि (a_n=(3n-2)2 ) है, तो \(a_4\) का मान क्या होगा?
If (a_n=(3n-2)2 ), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (81)
B (100)
C (121)
D (144)
Explanation opens after your attempt
Step 1
Concept
(a_4=(12-2)2 =100). In exams, find the value inside the bracket first.
Step 2
Why this answer is correct
The correct answer is B. (100). (a_4=(12-2)2 =100). In exams, find the value inside the bracket first.
Step 3
Exam Tip
(a_4=(12-2)2 =100) है। परीक्षा में कोष्ठक का मान पहले निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(1,16,49,100,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(1,16,49,100,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (a_n=(3n-2)2 )
B \(a_n=3n^2-2\)
C \(a_n=n^2+15\)
D (a_n=(n+1)3 )
Explanation opens after your attempt
Correct Answer
A. (a_n=(3n-2)2 )
Step 1
Concept
The squares of (3n-2) give (1,16,49,100). In exams, form the base first and then square it.
Step 2
Why this answer is correct
The correct answer is A. (a_n=(3n-2)2 ). The squares of (3n-2) give (1,16,49,100). In exams, form the base first and then square it.
Step 3
Exam Tip
(3n-2) के वर्ग से (1,16,49,100) मिलते हैं। परीक्षा में पहले आधार बनाकर फिर वर्ग करें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=150-11n\) है, तो \(a_7\) का मान क्या होगा?
If \(a_n=150-11n\), what is the value of \(a_7\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (71)
B (73)
C (75)
D (77)
Explanation opens after your attempt
Step 1
Concept
\(a_7=150-77=73\). In exams, multiply first in a decreasing formula.
Step 2
Why this answer is correct
The correct answer is B. (73). \(a_7=150-77=73\). In exams, multiply first in a decreasing formula.
Step 3
Exam Tip
\(a_7=150-77=73\) है। परीक्षा में घटते सूत्र में गुणन पहले करें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(139,128,117,106,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(139,128,117,106,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=139-11n\)
B \(a_n=150-11n\)
C \(a_n=11n+128\)
D \(a_n=150+n\)
Explanation opens after your attempt
Correct Answer
B. \(a_n=150-11n\)
Step 1
Concept
At (n=1) it gives (139), and at (n=2) it gives (128), so \(a_n=150-11n\). In exams, match the first term of a decreasing sequence.
Step 2
Why this answer is correct
The correct answer is B. \(a_n=150-11n\). At (n=1) it gives (139), and at (n=2) it gives (128), so \(a_n=150-11n\). In exams, match the first term of a decreasing sequence.
Step 3
Exam Tip
(n=1) पर (139) और (n=2) पर (128) मिलता है, इसलिए \(a_n=150-11n\) है। परीक्षा में घटते अनुक्रम का पहला पद मिलाएँ।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=8n-5\) है, तो कौन-सा पद (155) के बराबर होगा?
If \(a_n=8n-5\), which term is equal to (155)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (n=18)
B (n=19)
C (n=20)
D (n=21)
Explanation opens after your attempt
Step 1
Concept
From (8n-5=155), we get (n=20). In exams, equate the formula to the given value to find the term number.
Step 2
Why this answer is correct
The correct answer is C. (n=20). From (8n-5=155), we get (n=20). In exams, equate the formula to the given value to find the term number.
Step 3
Exam Tip
(8n-5=155) से (n=20) मिलता है। परीक्षा में पद संख्या के लिए सूत्र को दिए मान के बराबर रखें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(4,15,26,37,\ldots\) में (125) कौन-सा पद है?
In the sequence \(4,15,26,37,\ldots\), which term is (125)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A दसवाँ पद / (10)th term
B ग्यारहवाँ पद / (11)th term
C बारहवाँ पद / (12)th term
D तेरहवाँ पद / (13)th term
Explanation opens after your attempt
Correct Answer
C. बारहवाँ पद / (12)th term
Step 1
Concept
Its rule is \(a_n=11n-7\), and (11n-7=125) gives (n=12). In exams, equate the given term to the general term.
Step 2
Why this answer is correct
The correct answer is C. बारहवाँ पद / (12)th term. Its rule is \(a_n=11n-7\), and (11n-7=125) gives (n=12). In exams, equate the given term to the general term.
Step 3
Exam Tip
इसका नियम \(a_n=11n-7\) है और (11n-7=125) से (n=12) है। परीक्षा में दिए पद को सामान्य पद के बराबर रखें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(3,8,17,32,\ldots\) के लिए सही सामान्य पद कौन-सा है?
Which general term is correct for the sequence \(3,8,17,32,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=2^n+n^2\)
B \(a_n=2n+1\)
C \(a_n=n^2+2\)
D \(a_n=3n^2\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=2^n+n^2\)
Step 1
Concept
\(2^n+n^2\) gives (3,8,17,32). In exams, check combined power-and-square rules.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=2^n+n^2\). \(2^n+n^2\) gives (3,8,17,32). In exams, check combined power-and-square rules.
Step 3
Exam Tip
\(2^n+n^2\) से (3,8,17,32) मिलते हैं। परीक्षा में घात और वर्ग वाले संयुक्त नियम जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=3^n+n^2-1\) है, तो \(a_3\) का मान क्या होगा?
If \(a_n=3^n+n^2-1\), what is the value of \(a_3\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (33)
B (35)
C (37)
D (39)
Explanation opens after your attempt
Step 1
Concept
\(a_3=27+9-1=35\). In exams, check the power, square, and constant subtraction.
Step 2
Why this answer is correct
The correct answer is B. (35). \(a_3=27+9-1=35\). In exams, check the power, square, and constant subtraction.
Step 3
Exam Tip
\(a_3=27+9-1=35\) है। परीक्षा में घात, वर्ग और स्थिर घटाव तीनों देखें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(3,12,35,96,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(3,12,35,96,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=3^n+n^2-1\)
B \(a_n=3n^2\)
C \(a_n=2^n+3n\)
D \(a_n=n^3+2\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=3^n+n^2-1\)
Step 1
Concept
\(3^n+n^2-1\) gives (3,12,35,96). In exams, check a power rule in rapid growth.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=3^n+n^2-1\). \(3^n+n^2-1\) gives (3,12,35,96). In exams, check a power rule in rapid growth.
Step 3
Exam Tip
\(3^n+n^2-1\) से (3,12,35,96) मिलते हैं। परीक्षा में तेज वृद्धि में घात वाला नियम जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=7\cdot2^{n-1}+4\) है, तो \(a_5\) का मान क्या होगा?
If \(a_n=7\cdot2^{n-1}+4\), what is the value of \(a_5\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (112)
B (116)
C (120)
D (124)
Explanation opens after your attempt
Step 1
Concept
\(a_5=7\cdot2^4+4=116\). In exams, apply the exponent (n-1) carefully.
Step 2
Why this answer is correct
The correct answer is B. (116). \(a_5=7\cdot2^4+4=116\). In exams, apply the exponent (n-1) carefully.
Step 3
Exam Tip
\(a_5=7\cdot2^4+4=116\) है। परीक्षा में (n-1) वाले घातांक को ध्यान से लगाएँ।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(11,18,32,60,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(11,18,32,60,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=7\cdot2^{n-1}+4\)
B \(a_n=11n\)
C \(a_n=2^n+9\)
D \(a_n=4n^2+7\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=7\cdot2^{n-1}+4\)
Step 1
Concept
\(7\cdot2^{n-1}+4\) gives the given terms. In exams, also check constant addition in geometric forms.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=7\cdot2^{n-1}+4\). \(7\cdot2^{n-1}+4\) gives the given terms. In exams, also check constant addition in geometric forms.
Step 3
Exam Tip
\(7\cdot2^{n-1}+4\) से दिए पद मिलते हैं। परीक्षा में गुणोत्तर रूप में स्थिर जोड़ भी जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=4n^2+5n-6\) है, तो \(a_3+a_5\) का मान क्या होगा?
If \(a_n=4n^2+5n-6\), what is the value of \(a_3+a_5\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (160)
B (162)
C (164)
D (166)
Explanation opens after your attempt
Step 1
Concept
\(a_3=45\) and \(a_5=119\), so the sum is (164). In exams, find both terms before adding.
Step 2
Why this answer is correct
The correct answer is C. (164). \(a_3=45\) and \(a_5=119\), so the sum is (164). In exams, find both terms before adding.
Step 3
Exam Tip
\(a_3=45\) और \(a_5=119\), इसलिए योग (164) है। परीक्षा में योग से पहले दोनों पद निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(3,20,45,78,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(3,20,45,78,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=4n^2+5n-6\)
B \(a_n=3n^2\)
C \(a_n=17n-14\)
D \(a_n=5n^2-2n\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=4n^2+5n-6\)
Step 1
Concept
\(4n^2+5n-6\) gives (3,20,45,78). In exams, choose a quadratic rule when second differences are constant.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=4n^2+5n-6\). \(4n^2+5n-6\) gives (3,20,45,78). In exams, choose a quadratic rule when second differences are constant.
Step 3
Exam Tip
\(4n^2+5n-6\) से (3,20,45,78) मिलते हैं। परीक्षा में दूसरे अंतर समान हों तो वर्गीय नियम चुनें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=n^3+3n^2-2\) है, तो \(a_4\) का मान क्या होगा?
If \(a_n=n^3+3n^2-2\), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (104)
B (106)
C (108)
D (110)
Explanation opens after your attempt
Step 1
Concept
\(a_4=64+48-2=110\). In exams, calculate the cube and square separately.
Step 2
Why this answer is correct
The correct answer is D. (110). \(a_4=64+48-2=110\). In exams, calculate the cube and square separately.
Step 3
Exam Tip
\(a_4=64+48-2=110\) है। परीक्षा में घन और वर्ग दोनों अलग निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,18,52,110,\ldots\) के लिए सही सामान्य पद कौन-सा है?
Which general term is correct for the sequence \(2,18,52,110,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=n^3+3n^2-2\)
B \(a_n=2n^3\)
C \(a_n=n^3+n^2\)
D \(a_n=16n-14\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=n^3+3n^2-2\)
Step 1
Concept
\(n^3+3n^2-2\) gives (2,18,52,110). In exams, test cube-based options with small (n).
Step 2
Why this answer is correct
The correct answer is A. \(a_n=n^3+3n^2-2\). \(n^3+3n^2-2\) gives (2,18,52,110). In exams, test cube-based options with small (n).
Step 3
Exam Tip
\(n^3+3n^2-2\) से (2,18,52,110) मिलते हैं। परीक्षा में घन आधारित विकल्पों को छोटे (n) से जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=2n^3+n^2+n\) है, तो \(a_3\) का मान क्या होगा?
If \(a_n=2n^3+n^2+n\), what is the value of \(a_3\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (62)
B (64)
C (66)
D (68)
Explanation opens after your attempt
Step 1
Concept
\(a_3=54+9+3=66\). In exams, add the cube, square, and linear parts.
Step 2
Why this answer is correct
The correct answer is C. (66). \(a_3=54+9+3=66\). In exams, add the cube, square, and linear parts.
Step 3
Exam Tip
\(a_3=54+9+3=66\) है। परीक्षा में घन, वर्ग और रैखिक भाग जोड़ें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(4,22,66,148,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(4,22,66,148,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=2n^3+n^2+n\)
B \(a_n=4n^2\)
C \(a_n=n^3+3n\)
D \(a_n=18n-14\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=2n^3+n^2+n\)
Step 1
Concept
\(2n^3+n^2+n\) gives (4,22,66,148). In exams, also check combined cubic rules.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=2n^3+n^2+n\). \(2n^3+n^2+n\) gives (4,22,66,148). In exams, also check combined cubic rules.
Step 3
Exam Tip
\(2n^3+n^2+n\) से (4,22,66,148) मिलते हैं। परीक्षा में संयुक्त घन नियम भी जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=\frac{3n^2+5n}{4}\) है, तो \(a_4\) का मान क्या होगा?
If \(a_n=\frac{3n^2+5n}{4}\), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (15)
B (16)
C (17)
D (18)
Explanation opens after your attempt
Step 1
Concept
\(a_4=\frac{48+20}{4}=17\). In exams, simplify the whole numerator and then divide by the denominator.
Step 2
Why this answer is correct
The correct answer is C. (17). \(a_4=\frac{48+20}{4}=17\). In exams, simplify the whole numerator and then divide by the denominator.
Step 3
Exam Tip
\(a_4=\frac{48+20}{4}=17\) है। परीक्षा में अंश पूरा सरल करके हर से भाग दें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,\frac{11}{2},\frac{21}{2},17,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(2,\frac{11}{2},\frac{21}{2},17,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=\frac{3n^2+5n}{4}\)
B (a_n=\frac{n(n+3)}{2})
C \(a_n=3n-1\)
D \(a_n=\frac{5n^2+n}{4}\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=\frac{3n^2+5n}{4}\)
Step 1
Concept
\(\frac{3n^2+5n}{4}\) gives the given terms. In exams, match fractional terms with options too.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=\frac{3n^2+5n}{4}\). \(\frac{3n^2+5n}{4}\) gives the given terms. In exams, match fractional terms with options too.
Step 3
Exam Tip
\(\frac{3n^2+5n}{4}\) से दिए पद मिलते हैं। परीक्षा में भिन्न पदों को भी विकल्पों से मिलाएँ।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=6n^2-n+4\) है, तो \(a_4:a_2\) क्या होगा?
If \(a_n=6n^2-n+4\), what is \(a_4:a_2\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (96:26)
B (48:13)
C (13:48)
D (46:13)
Explanation opens after your attempt
Correct Answer
B. (48:13)
Step 1
Concept
\(a_4=96\) and \(a_2=26\), so the simplified ratio is (48:13). In exams, do not forget to simplify the ratio.
Step 2
Why this answer is correct
The correct answer is B. (48:13). \(a_4=96\) and \(a_2=26\), so the simplified ratio is (48:13). In exams, do not forget to simplify the ratio.
Step 3
Exam Tip
\(a_4=96\) और \(a_2=26\), इसलिए सरल अनुपात (48:13) है। परीक्षा में अनुपात सरल करना न भूलें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(9,26,55,96,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(9,26,55,96,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=6n^2-n+4\)
B \(a_n=9n\)
C \(a_n=17n-8\)
D \(a_n=5n^2+4n\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=6n^2-n+4\)
Step 1
Concept
\(6n^2-n+4\) gives (9,26,55,96). In exams, check a quadratic rule when second differences are constant.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=6n^2-n+4\). \(6n^2-n+4\) gives (9,26,55,96). In exams, check a quadratic rule when second differences are constant.
Step 3
Exam Tip
\(6n^2-n+4\) से (9,26,55,96) मिलते हैं। परीक्षा में दूसरे अंतर समान हों तो वर्गीय नियम देखें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=5^n+n-4\) है, तो \(a_3\) का मान क्या होगा?
If \(a_n=5^n+n-4\), what is the value of \(a_3\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (120)
B (122)
C (124)
D (126)
Explanation opens after your attempt
Step 1
Concept
\(a_3=125+3-4=124\). In exams, keep both the power and linear part correct.
Step 2
Why this answer is correct
The correct answer is C. (124). \(a_3=125+3-4=124\). In exams, keep both the power and linear part correct.
Step 3
Exam Tip
\(a_3=125+3-4=124\) है। परीक्षा में घात और रैखिक भाग दोनों सही रखें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,23,124,625,\ldots\) के लिए सही सामान्य पद कौन-सा है?
Which general term is correct for the sequence \(2,23,124,625,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=5^n+n-4\)
B \(a_n=5n-3\)
C \(a_n=2^n+5\)
D \(a_n=n^5-4\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=5^n+n-4\)
Step 1
Concept
\(5^n+n-4\) gives (2,23,124,625). In exams, also check the small linear part in a power rule.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=5^n+n-4\). \(5^n+n-4\) gives (2,23,124,625). In exams, also check the small linear part in a power rule.
Step 3
Exam Tip
\(5^n+n-4\) से (2,23,124,625) मिलते हैं। परीक्षा में घात वाले नियम में छोटा रैखिक भाग भी जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=13n-10\) है, तो पहले पाँच पदों का औसत क्या होगा?
If \(a_n=13n-10\), what is the average of the first five terms?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (29)
B (31)
C (33)
D (35)
Explanation opens after your attempt
Step 1
Concept
The first five terms are (3,16,29,42,55), and the average is (29). In exams, divide the sum by the number of terms.
Step 2
Why this answer is correct
The correct answer is A. (29). The first five terms are (3,16,29,42,55), and the average is (29). In exams, divide the sum by the number of terms.
Step 3
Exam Tip
पहले पाँच पद (3,16,29,42,55) हैं और औसत (29) है। परीक्षा में औसत के लिए योग को पदों की संख्या से भाग दें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(3,16,29,42,\ldots\) में (159) कौन-सा पद है?
In the sequence \(3,16,29,42,\ldots\), which term is (159)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A बारहवाँ पद / (12)th term
B तेरहवाँ पद / (13)th term
C चौदहवाँ पद / (14)th term
D पंद्रहवाँ पद / (15)th term
Explanation opens after your attempt
Correct Answer
B. तेरहवाँ पद / (13)th term
Step 1
Concept
Its rule is \(a_n=13n-10\), and (13n-10=159) gives (n=13). In exams, equate the given term to the general term.
Step 2
Why this answer is correct
The correct answer is B. तेरहवाँ पद / (13)th term. Its rule is \(a_n=13n-10\), and (13n-10=159) gives (n=13). In exams, equate the given term to the general term.
Step 3
Exam Tip
इसका नियम \(a_n=13n-10\) है और (13n-10=159) से (n=13) है। परीक्षा में दिए पद को सामान्य पद के बराबर रखें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=n^4-n^2\) है, तो \(a_3\) का मान क्या होगा?
If \(a_n=n^4-n^2\), what is the value of \(a_3\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (68)
B (70)
C (72)
D (74)
Explanation opens after your attempt
Step 1
Concept
\(a_3=81-9=72\). In exams, calculate the fourth power and square separately.
Step 2
Why this answer is correct
The correct answer is C. (72). \(a_3=81-9=72\). In exams, calculate the fourth power and square separately.
Step 3
Exam Tip
\(a_3=81-9=72\) है। परीक्षा में चौथी घात और वर्ग अलग-अलग निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(0,12,72,240,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(0,12,72,240,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=n^4-n^2\)
B \(a_n=n^3+n\)
C \(a_n=12n\)
D \(a_n=2n^4\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=n^4-n^2\)
Step 1
Concept
\(n^4-n^2\) gives (0,12,72,240). In exams, test higher-power options with small (n).
Step 2
Why this answer is correct
The correct answer is A. \(a_n=n^4-n^2\). \(n^4-n^2\) gives (0,12,72,240). In exams, test higher-power options with small (n).
Step 3
Exam Tip
\(n^4-n^2\) से (0,12,72,240) मिलते हैं। परीक्षा में उच्च घात वाले विकल्पों को छोटे (n) से जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=4^n+n-3\) है, तो \(a_4\) का मान क्या होगा?
If \(a_n=4^n+n-3\), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (253)
B (255)
C (257)
D (259)
Explanation opens after your attempt
Step 1
Concept
\(a_4=256+4-3=257\). In exams, add the full linear part after the power.
Step 2
Why this answer is correct
The correct answer is C. (257). \(a_4=256+4-3=257\). In exams, add the full linear part after the power.
Step 3
Exam Tip
\(a_4=256+4-3=257\) है। परीक्षा में घात के बाद पूरा रैखिक भाग जोड़ें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,15,64,257,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(2,15,64,257,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=4^n+n-3\)
B \(a_n=4n-2\)
C \(a_n=2^n+4n\)
D \(a_n=n^4+1\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=4^n+n-3\)
Step 1
Concept
\(4^n+n-3\) gives (2,15,64,257). In exams, check a power rule in rapid growth.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=4^n+n-3\). \(4^n+n-3\) gives (2,15,64,257). In exams, check a power rule in rapid growth.
Step 3
Exam Tip
\(4^n+n-3\) से (2,15,64,257) मिलते हैं। परीक्षा में तेज वृद्धि में घात वाला नियम जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=2n^2+9n+1\) है, तो \(a_5\) का मान क्या होगा?
If \(a_n=2n^2+9n+1\), what is the value of \(a_5\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (92)
B (94)
C (96)
D (98)
Explanation opens after your attempt
Step 1
Concept
\(a_5=50+45+1=96\). In exams, add both the square and linear parts.
Step 2
Why this answer is correct
The correct answer is C. (96). \(a_5=50+45+1=96\). In exams, add both the square and linear parts.
Step 3
Exam Tip
\(a_5=50+45+1=96\) है। परीक्षा में वर्ग और रैखिक भाग दोनों जोड़ें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(12,27,46,69,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(12,27,46,69,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=2n^2+9n+1\)
B \(a_n=12n\)
C \(a_n=15n-3\)
D \(a_n=3n^2+8n\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=2n^2+9n+1\)
Step 1
Concept
\(2n^2+9n+1\) gives (12,27,46,69). In exams, test the quadratic rule with the first four terms.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=2n^2+9n+1\). \(2n^2+9n+1\) gives (12,27,46,69). In exams, test the quadratic rule with the first four terms.
Step 3
Exam Tip
\(2n^2+9n+1\) से (12,27,46,69) मिलते हैं। परीक्षा में वर्गीय नियम को पहले चार पदों से जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=200-12n\) है, तो \(a_9\) का मान क्या होगा?
If \(a_n=200-12n\), what is the value of \(a_9\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (86)
B (88)
C (90)
D (92)
Explanation opens after your attempt
Step 1
Concept
\(a_9=200-108=92\). In exams, multiply first in a decreasing formula.
Step 2
Why this answer is correct
The correct answer is D. (92). \(a_9=200-108=92\). In exams, multiply first in a decreasing formula.
Step 3
Exam Tip
\(a_9=200-108=92\) है। परीक्षा में घटते सूत्र में गुणन पहले करें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(188,176,164,152,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(188,176,164,152,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=188-12n\)
B \(a_n=200-12n\)
C \(a_n=12n+176\)
D \(a_n=200+n\)
Explanation opens after your attempt
Correct Answer
B. \(a_n=200-12n\)
Step 1
Concept
At (n=1) it gives (188), and at (n=2) it gives (176), so \(a_n=200-12n\). In exams, check the first two terms of a decreasing sequence.
Step 2
Why this answer is correct
The correct answer is B. \(a_n=200-12n\). At (n=1) it gives (188), and at (n=2) it gives (176), so \(a_n=200-12n\). In exams, check the first two terms of a decreasing sequence.
Step 3
Exam Tip
(n=1) पर (188) और (n=2) पर (176) मिलता है, इसलिए \(a_n=200-12n\) है। परीक्षा में घटते अनुक्रम के पहले दो पद जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=\frac{n(5n-1)}{2}\) है, तो \(a_6\) का मान क्या होगा?
If \(a_n=\frac{n(5n-1)}{2}\), what is the value of \(a_6\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (81)
B (83)
C (85)
D (87)
Explanation opens after your attempt
Step 1
Concept
\(a_6=\frac{6\times29}{2}=87\). In exams, find the bracket value first and then divide.
Step 2
Why this answer is correct
The correct answer is D. (87). \(a_6=\frac{6\times29}{2}=87\). In exams, find the bracket value first and then divide.
Step 3
Exam Tip
\(a_6=\frac{6\times29}{2}=87\) है। परीक्षा में पहले कोष्ठक का मान निकालें और फिर भाग दें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(2,9,21,38,\ldots\) के लिए सही सामान्य पद कौन-सा है?
Which general term is correct for the sequence \(2,9,21,38,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (a_n=\frac{n(5n-1)}{2})
B (a_n=\frac{n(n+5)}{2})
C \(a_n=7n-5\)
D \(a_n=2n^2\)
Explanation opens after your attempt
Correct Answer
A. (a_n=\frac{n(5n-1)}{2})
Step 1
Concept
(\frac{n(5n-1)}{2}) gives (2,9,21,38). In exams, also check fractional-form general terms.
Step 2
Why this answer is correct
The correct answer is A. (a_n=\frac{n(5n-1)}{2}). (\frac{n(5n-1)}{2}) gives (2,9,21,38). In exams, also check fractional-form general terms.
Step 3
Exam Tip
(\frac{n(5n-1)}{2}) से (2,9,21,38) मिलते हैं। परीक्षा में भिन्न रूप वाले सामान्य पद भी जाँचें।
Login to save your score, XP, coins and progress. Login
यदि (a_n=(n+1)3 -n) है, तो \(a_4\) का मान क्या होगा?
If (a_n=(n+1)3 -n), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (117)
B (119)
C (121)
D (123)
Explanation opens after your attempt
Step 1
Concept
\(a_4=5^3-4=121\). In exams, find the power of the bracket first.
Step 2
Why this answer is correct
The correct answer is C. (121). \(a_4=5^3-4=121\). In exams, find the power of the bracket first.
Step 3
Exam Tip
\(a_4=5^3-4=121\) है। परीक्षा में पहले कोष्ठक की घात निकालें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(7,25,61,121,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(7,25,61,121,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (a_n=(n+1)3 -n)
B \(a_n=n^3+6\)
C \(a_n=7n\)
D \(a_n=2^n+5n\)
Explanation opens after your attempt
Correct Answer
A. (a_n=(n+1)3 -n)
Step 1
Concept
((n+1)3 -n) gives (7,25,61,121). In exams, check shifted cube rules.
Step 2
Why this answer is correct
The correct answer is A. (a_n=(n+1)3 -n). ((n+1)3 -n) gives (7,25,61,121). In exams, check shifted cube rules.
Step 3
Exam Tip
((n+1)3 -n) से (7,25,61,121) मिलते हैं। परीक्षा में स्थानांतरित घन नियमों को जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=3\cdot2^n+2n^2\) है, तो \(a_4\) का मान क्या होगा?
If \(a_n=3\cdot2^n+2n^2\), what is the value of \(a_4\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (76)
B (78)
C (80)
D (82)
Explanation opens after your attempt
Step 1
Concept
\(a_4=3\cdot16+2\times16=80\). In exams, add both the power and square parts.
Step 2
Why this answer is correct
The correct answer is C. (80). \(a_4=3\cdot16+2\times16=80\). In exams, add both the power and square parts.
Step 3
Exam Tip
\(a_4=3\cdot16+2\times16=80\) है। परीक्षा में घात और वर्ग दोनों जोड़ें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(8,20,42,80,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(8,20,42,80,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=3\cdot2^n+2n^2\)
B \(a_n=8n\)
C \(a_n=2^n+6n\)
D \(a_n=4n^2+4\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=3\cdot2^n+2n^2\)
Step 1
Concept
\(3\cdot2^n+2n^2\) gives the given terms. In exams, match combined power-and-square rules.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=3\cdot2^n+2n^2\). \(3\cdot2^n+2n^2\) gives the given terms. In exams, match combined power-and-square rules.
Step 3
Exam Tip
\(3\cdot2^n+2n^2\) से दिए पद मिलते हैं। परीक्षा में घात और वर्ग वाले संयुक्त नियम मिलाएँ।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=7n^2-4n+1\) है, तो \(a_5\) का मान क्या होगा?
If \(a_n=7n^2-4n+1\), what is the value of \(a_5\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (150)
B (152)
C (154)
D (156)
Explanation opens after your attempt
Step 1
Concept
\(a_5=175-20+1=156\). In exams, subtract the linear part from the quadratic part.
Step 2
Why this answer is correct
The correct answer is D. (156). \(a_5=175-20+1=156\). In exams, subtract the linear part from the quadratic part.
Step 3
Exam Tip
\(a_5=175-20+1=156\) है। परीक्षा में वर्गीय भाग से रैखिक भाग घटाएँ।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(4,21,52,97,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(4,21,52,97,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=7n^2-4n+1\)
B \(a_n=4n^2\)
C \(a_n=17n-13\)
D \(a_n=5n^2+2n\)
Explanation opens after your attempt
Correct Answer
A. \(a_n=7n^2-4n+1\)
Step 1
Concept
\(7n^2-4n+1\) gives (4,21,52,97). In exams, identify a quadratic rule by equal second differences.
Step 2
Why this answer is correct
The correct answer is A. \(a_n=7n^2-4n+1\). \(7n^2-4n+1\) gives (4,21,52,97). In exams, identify a quadratic rule by equal second differences.
Step 3
Exam Tip
\(7n^2-4n+1\) से (4,21,52,97) मिलते हैं। परीक्षा में दूसरे अंतर समान देखकर वर्गीय नियम पहचानें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(8,27,56,95,\ldots\) का सामान्य पद क्या है?
What is the general term of the sequence \(8,27,56,95,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=19n-11\)
B \(a_n=4n^2+4n\)
C \(a_n=5n^2+2n+1\)
D \(a_n=5n^2+4n-1\)
Explanation opens after your attempt
Correct Answer
D. \(a_n=5n^2+4n-1\)
Step 1
Concept
\(5n^2+4n-1\) gives (8,27,56,95). In exams, test the rule on the first four terms.
Step 2
Why this answer is correct
The correct answer is D. \(a_n=5n^2+4n-1\). \(5n^2+4n-1\) gives (8,27,56,95). In exams, test the rule on the first four terms.
Step 3
Exam Tip
\(5n^2+4n-1\) से (8,27,56,95) मिलते हैं। परीक्षा में पहले चार पदों पर नियम जाँचें।
Login to save your score, XP, coins and progress. Login
यदि \(a_n=\frac{n(3n+5)}{2}\) है, तो \(a_8\) का मान क्या होगा?
If \(a_n=\frac{n(3n+5)}{2}\), what is the value of \(a_8\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A (108)
B (112)
C (116)
D (120)
Explanation opens after your attempt
Step 1
Concept
\(a_8=\frac{8\times29}{2}=116\). In exams, find the bracket value first and simplify.
Step 2
Why this answer is correct
The correct answer is C. (116). \(a_8=\frac{8\times29}{2}=116\). In exams, find the bracket value first and simplify.
Step 3
Exam Tip
\(a_8=\frac{8\times29}{2}=116\) है। परीक्षा में पहले कोष्ठक का मान निकालकर सरल करें।
Login to save your score, XP, coins and progress. Login
अनुक्रम \(3,14,59,266,\ldots\) के लिए सही स्पष्ट नियम कौन-सा है?
Which explicit rule is correct for the sequence \(3,14,59,266,\ldots\)?
#sequences
#progressions
#explicit-rule
#class-9
#expert
50 50-50 2 wrong hide
⏭ Skip Next question
+10 Time+ 10 sec extra
? Hint Small clue
A \(a_n=3n^2\)
B \(a_n=2\cdot5^{n-1}+n^2\)
C \(a_n=5^n-n\)
D \(a_n=n^3+2n\)
Explanation opens after your attempt
Correct Answer
B. \(a_n=2\cdot5^{n-1}+n^2\)
Step 1
Concept
\(2\cdot5^{n-1}+n^2\) gives the given terms. In exams, check both the power and square in rapid growth.
Step 2
Why this answer is correct
The correct answer is B. \(a_n=2\cdot5^{n-1}+n^2\). \(2\cdot5^{n-1}+n^2\) gives the given terms. In exams, check both the power and square in rapid growth.
Step 3
Exam Tip
\(2\cdot5^{n-1}+n^2\) से दिए पद मिलते हैं। परीक्षा में तेज वृद्धि में घात और वर्ग दोनों जाँचें।
Login to save your score, XP, coins and progress. Login
