Integral Calculus Question 459

Question: $ \int_{{}}^{{}}{{{\sin }^{3}}x\ dx} $ is equal to

[SCRA 1996]

Options:

A) $ {{\sin }^{2}}x+1 $

B) $ \sin x^{2}+x^{2}+1 $

C) $ \frac{{{\cos }^{3}}x}{3}-\cos x $

D) $ \frac{1}{4}{{\sin }^{4}}x-\frac{3}{4}{{\sin }^{2}}x $

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Answer:

Correct Answer: C

Solution:

$ \int_{{}}^{{}}{{{\sin }^{3}}x,dx}=\int_{{}}^{{}}{{{\sin }^{2}}x,.,\sin x,dx} $ $ =\int_{{}}^{{}}{\sin x(1-{{\cos }^{2}}x),dx} $ $ =\int_{{}}^{{}}{\sin x,dx}-\int_{{}}^{{}}{{{\cos }^{2}}x,.,\sin x,dx} $ $ =-\cos x+\frac{{{\cos }^{3}}x}{3} $ .