Integral Calculus Question 435

Question: $ \int_{{}}^{{}}{e^{x}{{\tan }^{2}}(e^{x})dx=} $

Options:

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

B) $ e^{x}(\tan e^{x}-1)+c $

C) $ \sec (e^{x})+c $

D) $ \tan (e^{x})-e^{x}+c $

Show Answer

Answer:

Correct Answer: D

Solution:

Put $ e^{x}=t\Rightarrow e^{x}dx=dt, $ then $ \int_{{}}^{{}}{e^{x}{{\tan }^{2}}(e^{x}),dx}=\int_{{}}^{{}}{{{\tan }^{2}}t,dt}=\int_{{}}^{{}}{({{\sec }^{2}}t-1),dt} $ $ =\tan t-t+c=\tan (e^{x})-e^{x}+c. $