Integral Calculus Question 462

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

[SCRA 1996]

Options:

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

B) $ \frac{{{\sin }^{2}}x}{3}+c $

C) $ \frac{{{\sin }^{3}}x}{3}+c $

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

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Answer:

Correct Answer: C

Solution:

$ I=\int_{{}}^{{}}{{{\sin }^{2}}x,.,\cos x,dx} $ . Put $ \sin x=t\Rightarrow \cos x,dx=dt $
$ \therefore ,I=\int_{{}}^{{}}{t^{2}dt}=\frac{t^{3}}{3}+c=\frac{{{\sin }^{3}}x}{3}+c $ .