If the integral ∫ex1+sin x cos xcos2 xdx is the of the

If the integral ∫ex1+sin x cos xcos2 xdx is the of the
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If the integral ex1+sin x cos xcos2 xdx is the of the form ex [f(x) + f'(x)]dx then the appropriate f(x) would be -

A.

sec2x

B.

sin x.cos x

C.

tan x

D.

sec x

Please scroll down to see the correct answer and solution guide.

Right Answer is: C

SOLUTION

We can approach this problem by simplifying the given expression

ex1+sin x cos xcos2 xdx

= ex(sec2x + tanx)

or ex(tanx + sec2x)

On comparing this with ex [f(x) + f'(x)] we see that sec2x is the derivative of tan x

So f(x) should be tan x