1. cos (-4пи/3) = cos 4pi/3 = cos(pi+pi/3) = - cos pi/3 = - 1/2

2. cos(пи/4)+cos(3пи/2)+cosпи+cos(пи/3) = √2/2 + 0 -1 + 1/2 = √2/2 - 1/2

3. ctg(3pi/2) = 0

4. sin(3пи/4)+sin(пи/2)+sin(-пи/4)+sin(2пи) = √2/2 +1 -√2/2 +0 = 1

5. ctg(пи/3) = 1/√3 - табличное значение

6. sin(5пи/6)+sin(пи/2)+sin(пи/3)+sin3пи = sin(pi-pi/6) +1+√3/2 +0 = 1/2 +1+√3/2

7. cos(-пи/6) =cos(pi/6) = √3/2

8. cos( -5пи/4) = cos(pi+pi/4) = -cos(pi/4) = -√2/2

9. tg (-3пи/2) - не существут