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MTH 102 MTH 102 Past Questions Objective Question

Question

Given that a is a positive constant, evaluate the definite integral: ∫a3a (2x+1)/x dx
Options
A 3a + ln4
B 4a + ln 3
Correct Answer
C -3a + ln 3
D 5a + ln 3
Correct Answer

Option B is the correct answer.

Detailed Explanation

First, integrate the expression (2x+1)/x:∫ (2x+1)/x dx = ∫ (2 + 1/x) dx = 2x + ln|x|.Now, evaluate the definite integral from a to 3a:[2x + ln|x|]a3a = (2(3a) + ln(3a)) - (2a + ln(a))= 6a + ln(3a) - 2a - ln(a)= (6a - 2a) + (ln(3a) - ln(a))= 4a + ln(3a/a)= 4a + ln(3).(Note: The original document's integral lower bound was OCR'd as '2', but 'a' is assumed to match the options provided, which is a common practice in such questions.)

Hint

Split the integrand into two terms: (2x/x) + (1/x). Remember the properties of logarithms for definite integrals.

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