Use the double–angle identity to transform to .

Apply the distributive property.

Multiply .

Multiply by .

Multiply by .

Apply pythagorean identity.

Add and .

Use the double–angle identity to transform to .

Move .

Apply pythagorean identity.

Add and .

Cancel the common factor.

Rewrite the expression.

Convert from to .

Expand (1-cos(2x))/(1+cos(2x))