Having trouble with these problems can anyone help with any of these questions? And if possible can you explain> been working on this assignment all day and these are the only ones left.

Find the reference angle for the given angle.

1. 220

2. -225

3. 415

Use an addition or subtraction formula to write the expression as a trigonometric function of one number, and then find its exact value.

1. cos(80)cos(10)-sin(80)sin(10)

2. cos (7pie/6) cos (-pie/ 2)-sin(7pie/6)sine(-pie/2)

3. sin (255)

5. cot (135)

6. sin (5pie/6)

Find the exact value

tan(-195)

tan( -5pie/12)