(1+sina-cosa)/(1+sina+cosa) =( 1+2sina/2cosa/2cos2a+sin2a/2)/(1+2sina/2cosa/2+cos2a/2-sin2a/2)=(2sin2a/2+2sina/2cosa/2)/(2cos2a/2+2sina/2cosa/2) =[2sina/2(sina/2+cosa/2)]/[2cosa/2(cosa/2+sina/2)] =(si...