यदि \(a_1=2\) और \(a_{n+1}=a_n+n^2+2n+1\) है तो \(a_4\) क्या होगा?
If \(a_1=2\) and \(a_{n+1}=a_n+n^2+2n+1\), what is \(a_4\)?
Explanation opens after your attempt
B. (31)
Concept
The terms are (2,6,15,31), so \(a_4=31\). Exam tip: recognize \(n^2+2n+1\) as ((n+1)2).
Why this answer is correct
The correct answer is B. (31). The terms are (2,6,15,31), so \(a_4=31\). Exam tip: recognize \(n^2+2n+1\) as ((n+1)2).
Exam Tip
पद (2,6,15,31) हैं इसलिए \(a_4=31\) है। \(n^2+2n+1\) को ((n+1)2) की तरह पहचानें।
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