यदि गुणोत्तर श्रेणी के पहले (4) पदों का योग (780) है और (a=12) तथा (r=4) है, तो कथन कैसा है?
If the sum of the first (4) terms of a geometric progression is (780) with (a=12) and (r=4), what is the statement?
Explanation opens after your attempt
A. सही क्योंकि \(S_4=780\)True because \(S_4=780\)
Concept
(S_4=\frac{12\(4^4-1\)}{4-1}=1020), so the statement is false. In exams, verify statement-type questions carefully.
Why this answer is correct
The correct answer is A. सही क्योंकि \(S_4=780\) / True because \(S_4=780\). (S_4=\frac{12\(4^4-1\)}{4-1}=1020), so the statement is false. In exams, verify statement-type questions carefully.
Exam Tip
(S_4=\frac{12\(4^4-1\)}{4-1}=1020) नहीं; सीधे योग (12+48+192+768=1020) है, इसलिए कथन गलत है।
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