To evaluate [3113611) (3055 (m) da: we use the identity 51112 (at) + cos2 (:3) = 1 to obtain / sin2(a:) (l) 003(3) dm. We then make the substitution u = C]. To evaluate / sin2(a:) cos5 (:3) dm we use the identity Sin2(:c) + 0032(m) = 1 to obtain / sin2(a:) (D) cos(a:) dm. We then make the substitution 1:. =