Cosec^2=1 cot^2A (how did u wrote this like this👇👇👇Cosec^2A=1 (1/√sec^

This question was asked in Ex 8.4, 2

Cosec^2=1 cot^2A (how did u wrote this like this👇👇👇
Cosec^2A=1 (1/√sec^2A-1)^2
In exercise 8.4 2 nd main
Explain it plz