In terms of Q5,Q6,Q7 you need to find the values which the inequalities have in common.
We know that sin(x) is > 0 when x is in [0,pi] and < 0 when x is in (pi,2pi). cos(x) is > 0 when x is [0,pi) and (3*pi/2,2pi]
With regards to trigonometric functions do you have to find a value for theta or is it something else? The reason I ask is because they give values for r which implies that you need to use that to find something.