L [7] 8. Evaluate 4-22 dr in the following steps. I (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/co (b) Using cos20+ sin 0 = 1, verify the following trigonometric identity: [3] I cos cot = csc 0 - sin 0. [5] (c) Using the results in parts (a) and (b), plus the given formula sheet, evaluate 4-22 dr.