Ineed some explanations on how to solve these problems. the first two are solving for theta θ.
i could really use , guys!

6. If you know one solution, you can find all of them. when . has a period of , which means . So we know that is another solution. But the same idea applies to this solution, so that also works, and so on... The general solution would be for any integer .

7. Similar idea. You probably know that when . has a period of , so adding any multiple of to this solution gives more solutions. Here , so we have or .

8. This quadratic can be factored:

The latter can never happen for real , since .

so the general solution would be .