Question

If $8\,cos\,2\theta+8\, sec\,2\theta=65, 0 <\, \theta <\, \frac{\pi}{2}$, then the value of $4\, cos \,4\theta$ is equal to

• A. $\frac{-33}{8}$
• B. $\frac{-31}{8}$
• C. $\frac{-31}{32}$
• D. $\frac{-33}{32}$
• E. $\frac{-31}{4}$

Answer 1

Answer: (B)

Correct answer is (b) $\frac{-31}{8}$