Question

prove this identity:

sec(y) - cos(y)= tan(y)sin(y)


THANK YOU!!

Answer 1

sec(y)=1/cos(y)

tan(y) = sin(y)/cos(y)

Low consider left and right hand sides:

LHS = 1/cos(y) - cos^2(y)/cos(y)

RHS = sin^2(y)/cos(y)

Now you've got everything over a common denominator, look at the top of each side, and you should see your way through.