If $\underset{n→∞}{\lim}n \cos\frac{π}{4n}\sin\frac{π}{4n} = k$ then k is
Answer & explanation
Correct answer: option 1
$\underset{n→∞}{\lim}n \cos\frac{π}{4n}\sin\frac{π}{4n} = k$
$⇒\underset{n→∞}{\lim}\frac{\sin\frac{π}{2n}}{\frac{2}{n}}= k⇒k=\frac{π}{4}$