Question

tan square A cos square A=1- cos square A

Answer 1

tan sq a =sin sq A/cos sq A. and

1-cos sq A =sin sq A. putting in to left we get

sin sq A/cos sq A - sin sq A........... then cross multi and cut

Answer 2

LHS=tan squareA.cos squareA
=sin squareA/cos squareA *cos squareA
=sin squareA
=1- cos squareA
so,LHS=RHS
proved
hope it helps you