cosecA−1cosecA+1=(cosA1+sinA)2
cosecA−1cosecA+1
In LHS, multiply the numerator and denominator with sin A.
=(1−sinA)(1+sinA)
Again multiply the numerator and denominator with (1+sinA).
=(1−sinA)(1+sinA) × (1+sinA)(1+sinA)
=1−sin2A(1+sinA)2
=cos2A(1+sinA)2
= (cosA(1+sinA))2
Since, LHS = RHS, it is proved.