Problem 12. (1 point) Evaluate the indefinite integral. cos (8x) dx 1 + sin (8x) Answer: +C Problem 13. (1 point) Evaluate the indefinite integral (9-x2) 19/2 dx +C Problem 14. (1 point) Evaluate the integral 7 dx ex - e-x Note: Use an upper-case "C" for the constant of integration