Question

Let $\frac{\pi}{2}<x<\pi$ be such that $\cot x=\frac{-5}{\sqrt{11}}$. Then
$(\sin\frac{11x}{2})(\sin 6x-\cos6x)+(\cos\frac{11x}{2})(\sin 6x+\cos 6x)$
is equal to

• A. $\frac{\sqrt{11}-1}{2\sqrt3}$
• B. $\frac{\sqrt{11}+1}{2\sqrt3}$
• C. $\frac{\sqrt{11}+1}{3\sqrt2}$
• D. $\frac{\sqrt{11}-1}{3\sqrt2}$

Answer 1

Answer: (B)

$\frac{\sqrt{11}+1}{2\sqrt3}$

Answer 2

The correct option is (B):$\frac{\sqrt{11}+1}{2\sqrt3}$.