Integral Calculus Question 259

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

[MP PET 1987, 92]

Options:

A) $ 2(\sec x+\tan x)-x+c $

B) $ 1/3{{(\sec x+\tan x)}^{3}}+c $

C) $ \sec x(\sec x+\tan x)+c $

D) $ 2(\sec x+\tan x)+c $

Show Answer

Answer:

Correct Answer: A

Solution:

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