Question

形如(3-5sina)/(4+5sina)+(4-5sina)/(3+5sina)的化简

Answer 1

=[(3-5sina)*(3+5sina)+(4-5sina)*(4+5sina)]/(4+5sina)*(3+5sina)

=[9-25sin^2 a+16-25sin^2 a]/(4+5sina)*(3+5sina)

=[25-50sin^2 a]/(4+5sina)*(3+5sina)