In a sequence, (a_1=2) and the successive differences are (3,7,11,15,\ldots). What will be (a_5)?
Answer and explanation
Correct answer: 38
Successive differences mean that each new term is obtained by adding the stated difference to the preceding term. Thus, \(a_2=2+3\), \(a_3=a_2+7\), \(a_4=a_3+11\), and \(a_5=a_4+15\). Therefore, \(a_5=2+3+7+11+15=38\). Option 40 would result from incorrectly adding 2 extra to the total. Exam tip: to find \(a_n\), add the first \(n-1\) successive differences to \(a_1\).
Frequently asked questions
What is the correct answer to this question?
38
Why is this the correct answer?
Successive differences mean that each new term is obtained by adding the stated difference to the preceding term. Thus, \(a_2=2+3\), \(a_3=a_2+7\), \(a_4=a_3+11\), and \(a_5=a_4+15\). Therefore, \(a_5=2+3+7+11+15=38\). Option 40 would result from incorrectly adding 2 extra to the total. Exam tip: to find \(a_n\), add the first \(n-1\) successive differences to \(a_1\).
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Sequences.
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