Integral Calculus Question 437

Question: . $ \int_{{}}^{{}}{{{\tan }^{4}}x\ dx=} $

Options:

A) $ {{\tan }^{3}}x-\tan x+x+c $

B) $ \frac{1}{3}{{\tan }^{3}}x-\tan x+x+c $

C) $ \frac{1}{3}{{\tan }^{3}}x+\tan x+x+c $

D) $ \frac{1}{3}{{\tan }^{3}}x+\tan x+2x+c $

Show Answer

Answer:

Correct Answer: B

Solution:

$ \int_{{}}^{{}}{{{\tan }^{4}}x,dx}=\int_{{}}^{{}}{{{\tan }^{2}}x({{\sec }^{2}}x-1),dx} $ $ =\int_{{}}^{{}}{{{\tan }^{2}}x{{\sec }^{2}}x,dx}-\int_{{}}^{{}}{{{\tan }^{2}}x,dx}=\frac{{{\tan }^{3}}x}{3}-\tan x+x+c $ .