Just a simple parabola, $ y = x^2 $ . So, doing the maths: $r sin \theta = r^2 (cos(\theta))^2$. Then, I have $ r = \frac{sin(\theta)}{(cos(\theta))^2}$ .
I'm interested when $ \frac{3\pi}{4} < \theta < \pi$.
But when I plot in Desmos Calculator, https://www.desmos.com/calculator/ms3eghkkgz, the polar and the cartesian equations at the same time, the result is not the same… I have no idea what I'm doing wrong, can you explain me please?