Hello, Hoopsaholic31!

Please check those two identities; there are typos.

. . As written, neither is true.

. What is ?

You're expected to know the identity: .

Therefore: .

(a) Let:Find the exact value of these two:

. .

. .

Then we have: . .[1]

We have: .

is in a right triangle with:

. . Then: . . . . And hence: .

Substitute into [1]: .

. . Therefore: .

Let . . . Let

We have: . .[2]

We have: .

. . Then: .

We have: .

. . Then: .

Substitute into [2]: .