(sinY/tgY)^2 +(cosY/ctgY)^2

Question

(sinY/tgY)^2 +(cosY/ctgY)^2

Answer 1

(sinY/tgY)²=(sinY/(sinY/cosY))²=((sinY*cosY)/sinY)²=cos²Y
(cosY/ctgY)²=(cosY/(cosY/sinY))²=((cosY*sinY/cosY)²=sin²Y
cos²Y+sin²Y=1