Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Integrate ∫ 2x³e^(-x⁴) dx.
Options
A (1/2)e^(-x⁴) + C
B -(1/2)e^(-x⁴) + C
Correct Answer
C (1/2)e^(x⁴) + C
D -(1/2)e^(x⁴) + C
Correct Answer

Option B is the correct answer.

Detailed Explanation

To solve ∫ 2x³e^(-x⁴) dx, use u-substitution. Let u = -x⁴. Differentiate u with respect to x: du/dx = -4x³, so du = -4x³ dx. This means x³ dx = -(1/4) du. Substitute these into the integral: ∫ 2e^u (-(1/4)) du = -(2/4) ∫ e^u du = -(1/2) ∫ e^u du. The integral of e^u is e^u. So, -(1/2)e^u + C. Substituting back u = -x⁴, the final answer is -(1/2)e^(-x⁴) + C.

Hint

Use u-substitution. Let u be the exponent of e. Ensure the derivative of u is correctly accounted for in the substitution.

Question Info