8. Evaluate [7] [3] [5] 4-x2 dr in the following steps. (a) Set up a Trigonometric Substitution with an appropriate right triangle and relation between x and the reference angle 0. Transform the above integral into cos 0 cot 0 de. 2/cos 0 (b) Using cos + sin = 1, verify the following trigonometric identity: cos cot = csc - sin 0. esponse Quest (c) Using the results in parts (a) and (b), plus the given formula sheet, evaluate 4-x2 dx. X