Someone help me with proving identities? and please show the work if you can!

See Below.

Step-by-step explanation:

11)

We have:

Rewrite:

Multiply:

Combine:

According to the Pythagorean Identity, sin²θ + cos²θ = 1. Hence:

Simplify:

12)

We have:

Pythagorean Identity:

From the Pythagorean Identity, if we divide both sides by cos²θ, we acquire that tan²θ + 1 = sec²θ. Hence:

Simplify:

13)

We have:

Rewrite:

Multiply both top and bottom by cosθsinθ. Hence:

By the Pythagorean Identity:

Simplify:

if x = 1, then the answer is 3.5