Integral Calculus Question 348

Question: $ \int_{{}}^{{}}{2\sin x}\cos x\ dx $ is equal to

[SCRA 1996]

Options:

A) $ \cos 2x+c $

B) $ \sin 2x+c $

C) $ {{\cos }^{2}}x+c $

D) $ {{\sin }^{2}}x+c $

Show Answer

Answer:

Correct Answer: D

Solution:

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