Can i know the steps to this answer?

(cos²Ф - 1) / sin Ф * 1/sin Ф=
1(cos²Ф-1) / (sin Ф* sinФ)=
(cos²Ф-1) / sin² Ф=


Fundamental relation of trigonometry:
sin²Ф + cos²Ф=1  ⇒  sin²Ф=1-cos²Ф  ⇒-sin²Ф=cos²Ф-1


-sin²Ф/sin²Ф=1

 (cos²Ф - 1) / sin Ф * 1/sin Ф=-1