52-54

52. Evaluate: integral of 1/(4 + x^2)^3/2 dx. A. x/(4sqrt(x^ 2 + 4)) + c B. -1/(4sqrt(x^ 2 + 4)) + c C. x/(4sqrt(x^ 2 + 4)) + c D. 1/(4sqrt(x^ 2 + 4)) + c 53. Evaluate: integral of (e^x) /(e^x + 1) dx A. In(ex + 1) + c B. In(e^-x + 1) + c C. In^2 (ex + 1) + c D. In^2 (ex + 1) + c 54. Which of the following differentials must be integrated by parts ? a. (Inx/x) dx b. sin (3x) dx