$\lim\limits_{n \rightarrow \infty} \frac{n^k \sin ^2 n !}{n+2}$, 0 < k < 1, is equal to:
Answer & explanation
Correct answer: option 3
$\lim\limits_{n \rightarrow \infty} \frac{n^k \sin ^2 n !}{n+2}=\lim\limits_{n \rightarrow \infty} \frac{n^k \sin ^2 n !}{n(1+2 / n)}$
$=\lim\limits_{n \rightarrow \infty} \frac{\sin ^2(n !)}{n^{1-k}\left(1+\frac{2}{n}\right)}=\frac{\text { a finite quantity }}{\infty}$
[Since sin2 n! always lies between 0 and 1. Also, since 1 - k > 0, hence n1 - k → ∞
Hence (3) is the correct answer. as n→ ∞]