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MTH 102 MTH 102 Past Questions Objective Question

Question

Simplify ∫ ln x dx.
Options
A <i>x ln x + x<sup>2</sup> + C</i>
B <i>x - x<sup>2</sup> ln x + C</i>
C <i>x ln x - x + C</i>
Correct Answer
D <i>x<sup>2</sup> - ln x<sup>2</sup> + C</i>
Correct Answer

Option C is the correct answer.

Detailed Explanation

To simplify ∫ ln x dx, we use integration by parts, which states ∫ u dv = uv - ∫ v du.Let u = ln x and dv = dx.Then, we find du and v:du = d/dx (ln x) dx = (1/x) dxv = ∫ dx = xSubstitute these into the integration by parts formula:∫ ln x dx = (ln x) * x - ∫ x * (1/x) dx= x ln x - ∫ 1 dx= x ln x - x + C.This matches option C.

Hint

Use integration by parts. A common trick for integrating ln x is to let u = ln x and dv = dx.

Question Info