Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Evaluate ∫ (e2x + e-2x) / (e2x - e-2x) dx.
Options
A (1/4) ln|e<sup>2x</sup> - e<sup>-2x</sup>| + C
B (1/2) ln|e<sup>2x</sup> + e<sup>-2x</sup>| + C
C (1/2) ln|e<sup>2x</sup> - e<sup>-2x</sup>| + C
Correct Answer
D (1/4) ln|e<sup>2x</sup> + e<sup>-2x</sup>| + C
Correct Answer

Option C is the correct answer.

Detailed Explanation

To evaluate the integral ∫ (e2x + e-2x) / (e2x - e-2x) dx, use u-substitution.Let u = e2x - e-2x.Then, find du/dx:du/dx = d/dx(e2x) - d/dx(e-2x)= (2e2x) - (-2e-2x)= 2e2x + 2e-2x= 2(e2x + e-2x).So, du = 2(e2x + e-2x) dx, which means (e2x + e-2x) dx = (1/2) du.Substitute u and du into the integral:∫ (1/u) * (1/2) du = (1/2) ∫ (1/u) du.The integral of (1/u) with respect to u is ln|u|.= (1/2) ln|u| + C.Finally, substitute back u = e2x - e-2x:= (1/2) ln|e2x - e-2x| + C.

Hint

Try a u-substitution with the denominator of the integrand. Remember the chain rule for derivatives of exponential functions.

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