Question

${\lim }_{h\to 0}\frac{co{s}^2(x+h)-co{s}^{2}x}{h}$ is equal to

• A. $co{s}^{2}x$
• B. - sin 2x
• C. - sin x cos x
• D. 2 sin x

Answer 1

Answer: (B)

Correct answer is (b) - sin 2x