How do I solve:

Using Sum & Difference Identities

1. tan ( - pi/12)

2. tan (alpha + beta); alpha (-3/5) ends QIII; Beta (-1/4) ends QII

3. cos (-1/5 + -1/4)

4. (sin A - sin B)^2 + (cos A - cos B)^2

Answers:

1. -2 + sq.root(3)

2.[ 192- 25 sq.root(15) ] / -119

3.[ 1 + 6 sq.root(10) ] / 20

4. -2 cos (A - B)

Thank you very much for your time! =)