Verified answer

easy

first write everythin in terms of siny and cosy

you take lcm u get cos4y - sin4y that equals (cos2y - sin2y)(cos2y + sin2y) (here cos 2y is cos square y)

second equals 1 and the first equals cos2y(here 2y is actual 2y)

and

down u get another sin2y + cos2y(means square) after takin in terms of siny and cosy and LCM

and finally after cancellation u get sinycosy in the denom so mult and divide by 2 and denom becomes equal to sin2y(actual 2y)

and u get 2 cot2y