Question

prove that (cos 15 degree+sin 15 degree)/(cos 15 degree-sin15degree)=root 3

Answer 1

LHS=(cos15+sin15)/(cos15-sin15)

=(cos (90-75)+cos15)/(cos (90-75)-sin15)

=(sin75+sin15)/(sin75-sin15)

=2sin45.cos30/2cos45.sin30

=cos30/sin30=cot30=root3= RHS