Trigonometry
posted by Trig on .
Prove that (cosy/1+siny) + (1+siny/cosy) = 2secy

Left Side
= cosy/(1+siny) + (1+siny)/cosy , notice the proper brackets !!
= (cos^ y + 1 + 2siny + sin^2 y)/[cosy(1+siny)]
= (2 + 2siny)/[cosy(1+siny)]
= 2(1+siny)/[cosy(1+siny)]
= 2/cosy
= 2secy
= Right Side