Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Simplify ∫ 3x2 ex3 dx
Options
A e<sup>x<sup>2</sup></sup> + C
B e<sup>x<sup>3</sup></sup> + C
Correct Answer
C e<sup>x<sup>4</sup></sup> + C
D e<sup>x<sup>5</sup></sup> + C
Correct Answer

Option B is the correct answer.

Detailed Explanation

This integral can be solved using a simple substitution.Let u = x3.Then, find the differential du by differentiating u with respect to x:du = d/dx(x3) dxdu = 3x2 dxNotice that 3x2 dx is exactly the remaining part of the integrand. Substitute u and du into the integral:∫ eu duThis is a standard integral:= eu + CFinally, substitute back u = x3:= ex3 + CThis matches option B.

Hint

Look for a substitution where the derivative of the chosen u is also present in the integrand.

Question Info