Integral Calculus Question 286

Question: $ \int_{{}}^{{}}{{{( \cos \frac{x}{2}-\sin \frac{x}{2} )}^{2}}dx=} $

Options:

A) $ x+\cos x+c $

B) $ 2{{\cos }^{2}}\frac{x}{2}+c $

C) $ \frac{1}{3}{{( \cos \frac{x}{2}-\frac{x}{2} )}^{3}}+c $

D) $ x-\cos x+c $

Show Answer

Answer:

Correct Answer: A

Solution:

$ \int_{{}}^{{}}{{{( \cos \frac{x}{2}-\sin \frac{x}{2} )}^{2}}dx} $ $ =\int_{{}}^{{}}{{ {{\cos }^{2}}\frac{x}{2}+{{\sin }^{2}}\frac{x}{2}-2\sin \frac{x}{2}\cos \frac{x}{2} }}dx $ $ =\int_{{}}^{{}}{(1-\sin x),dx}=x+\cos x+c. $