1 . cosθ=12x+1x

• A. $-\frac{1}{2}\left(x+\frac{1}{x^2}\right)$
• B. $\frac{1}{2}\left(x-\frac{1}{x^2}\right)$
• C. $\frac{1}{2}\left(x^2+\frac{1}{x^2}\right)$
• D. $\frac{1}{2}\left(\frac{1}{x^2}-x\right)$

Answer: Option D

Explanation: