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MTH 102 MTH 102 Past Questions Objective Question

Question

Integrate ∫ ecos x sin x dx.
Options
A e<sup>sin x</sup>
B -e<sup>cos x</sup>
Correct Answer
C e<sup>cos x</sup>
D sin x
Correct Answer

Option B is the correct answer.

Detailed Explanation

This integral can be solved using a simple substitution.Let u = cos x.Then, differentiate u with respect to x: du/dx = -sin x.This means sin x dx = -du.Substitute these into the integral:∫ ecos x sin x dx = ∫ eu (-du) = -∫ eu du.The integral of eu is eu.So, -∫ eu du = -eu + C.Substitute back u = cos x: -ecos x + C.This matches option B.

Hint

Consider a substitution where u is the exponent of e.

Question Info