(a) Show that sin(I) 1 + cos2 (2) dx = ? ". Justify your answer fully. (b) Let f(x) be continuous, and a be any constant. Explain carefully why J." s()da = [" f(a-2) da. C Find x sin() dr. 1 + cos? (I ) The results of parts (a) and (b) above can help. You may use without proof the identities sin(7 + 0) = - sin(0) and cos(7 + 0) = - cos(0)