Sine and cosine at max are 1. Cosine is X and Sine is Y. The values of them repeat as their graphs are waves. As you can see here
So here `3pi/4` and `5pi/4` can both equal theta
theta can be 135 degrees or it can be 225 degrees
The above solution is right
this is the continuation
value of `theta = (3pi)/4 and (5pi)/4`
`cos(theta)` is negative in the 2nd and 3rd quadrants. Looking at a unit circle, the values of theta that satisfy this are 135 and 225 degrees.