Question

Cot(90°-A)tan A/sec²A -sin²A=0

Answer 1

tan²A/sec²A-sin²A=0
sin²A-sin²A=0
LHS=RHS
Hence proved

Answer 2

LHS=tanA×tanA/sec²A. - sin²A
=tan²A/sec²A - sin²A
=sin²A cos²A/cos²A - sin²A
=sin²A- sin²A
=0=RHS
hence proved