20 points & Brainliest to the one who gets ALL of them correct! NEED HELP ASAP!!! Due today!!!

Verify these Identities & SHOW YOUR WORK:

1. cosx−cosxsin²x = cos³x

2. [tex]\frac{sinx}{1+cosx}[/tex] = [tex]\frac{1-cosx}{sinx}[/tex]

3. cos⁴b−sin⁴b = 1−2sin²b

4. [tex]\frac{siny+cosy}{siny}- \frac{cosy-siny}{cosy}[/tex] = [tex]\frac{secy}{cosy}[/tex]

5. (secx−tanx)² = [tex]\frac{1-sinx}{1+sinx}[/tex]

HELP!!!