Question

prove 1-cos^2A/cosA+1=1-cosA

Answer 1

1-cos²A/ 1 + cos A = 1-cos A
(1-cosA) (1+cosA) /(1+cosA) = 1-cosA
{a²-b² = (a+b) (a-b)}
proved...

Answer 2

we put a2-b2 formula we get (a+b)(a-b)in this identity LHS=1-cos2A/cosa+1=(1+cosA)(1-cosA)/1+cosA=1-cosA hence LHS=RHS proved