Question

In polar coordinates, I tried plotting r^2=8cos(2theta). Mathematica shows me that it's a leminiscate that crosses the origin at pi/2. Shouldn't pi/2 give 8cos(pi) which gives -8? I don't get it. Is it because of the r squared that gives imaginary values?

Answer 1

Are you sure it's crossing the origin at pi/2?
It looks like it's crossing the origin at pi/4.