Hey.
Okay, so I'm doing this question and have no idea how to find all the solution for cosΘ = 1/√2 when the domain is 0≤Θ≤2π (that's a pi symbol)
Here's what I have worked out so far.
cosΘ = 1/√2
= π/4
cos is positive in the 1st and 4th quadrants.

I know the second answer is 7π/4. How did the 7 get in the result? Is there an equation I have to do to get it?

Also, I am having trouble with cosΘ = 0 when the domain is the same as above.

Please help!
Thank you.