(5) Compute the following indefinite integral using the method of trigonometric substitution. Express the final answer in terms of the variable r. The following power-reducing formulas may be useful: sin (0) = 1 - cos (20) cos- (8) = 1 + cos(20) 2 The following double-angle formulas may be useful: sin(20) = 2 sin(8) cos(8), cos(20) = cos(0) - sin? (8) = 2 cos2(8) - 1