if we divide the left side by the right side and it simplifies to 1 then its proved
cot^2 A (sec A - 1)(1 + sec A) cot^2 A ( sec^A - 1) -------------------------------------- = -------------------------- sec^2 A ( sinA + 1)(1 - sinA) sec^2 A ( 1 - sin^2 A)
Now sec^2 A - 1 = tan^2 A and 1 - sin^2 A = cos ^2A so the fraction becomes
cot^2 A . tan^2 A ---------------------- sec^2 A . cos^2A
Now cot^2 A = 1 / tan^2 A and 1/ sec^2 A = cos^2 A so we have
