Hey, everyone! We're on our Polar Unit in Pre-Calc and I'm completely lost when it comes to finding simultaneous points of intersections. I understand the method, but I just can't seem to get past step 1 much to my chagrin.

Take for example,

r = 1 - sinθ

r = cos2θ

Now, I set the two equal to each other.

1 - sinθ = cos2θ

And that's about as far as I get despite trying to substitute cos2θ with 1-2sin^2θ.

Any help would be greatly appreciated!