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MTH 102 MTH 102 Past Questions Objective Question

Question

Evaluate the integral: ∫ x/(x-1) dx
Options
A ln(x + 1)
B x + ln(x - 1)
Correct Answer
C e^(x+1)/x
D ln((x-1)/x)
Correct Answer

Option B is the correct answer.

Detailed Explanation

To evaluate ∫ x/(x-1) dx, we can use algebraic manipulation or a substitution.Let u = x - 1, then x = u + 1 and dx = du.The integral becomes ∫ (u + 1)/u du = ∫ (1 + 1/u) du.Integrating term by term: ∫ 1 du + ∫ 1/u du = u + ln|u| + C.Substitute back u = x - 1: (x - 1) + ln|x - 1| + C.Since C - 1 is still an arbitrary constant, we can write it as x + ln|x - 1| + C.Option B matches this form, assuming x-1 > 0 for the logarithm.

Hint

Try rewriting the integrand as a sum of simpler terms. Hint: x/(x-1) = (x-1+1)/(x-1).

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