Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Obtain the integral ∫ log x dx
Options
A x(log x + 1)
B x(log x - 1)
Correct Answer
C -x(log x + 1)
D x(1 - log x)
Correct Answer

Option B is the correct answer.

Detailed Explanation

We use integration by parts: ∫ u dv = uv - ∫ v du.Let u = log x (assuming natural logarithm, ln x) and dv = dx.Then du = (1/x) dx and v = x.∫ log x dx = x log x - ∫ x (1/x) dx= x log x - ∫ 1 dx= x log x - x + C= x (log x - 1) + C.

Hint

Use integration by parts with u = log x and dv = dx.

Question Info