=sin3t=sin(t+2t)=sintcos2t+costsin2t=sint(cost)^2-(sint)^3+2sint(cost)^2=3sint(cost)^2-(sint)^3
r^4=3rsint(rcost)^2-(rsint)^3
(x^2+y^2)^2=3yx^2-y^3
x^4+4y^2x^2-3yx^2+y^3+y^4=0
=sin3t=sin(t+2t)=sintcos2t+costsin2t=sint(cost)^2-(sint)^3+2sint(cost)^2=3sint(cost)^2-(sint)^3
r^4=3rsint(rcost)^2-(rsint)^3
(x^2+y^2)^2=3yx^2-y^3
x^4+4y^2x^2-3yx^2+y^3+y^4=0