Question

MORE MATH: https://snipboard.io/pimZdz.jpg

Answer 1

Going from step 1 to 2 they only changed sec(x) to 1/cos(x). Do you recall what this identity is called?

Here’s a reference to review if you’re not sure: (source: Owlcation)

Answer 2

Reciprocal identity?

Answer 3

Yup good