The question im looking at states: Prove that the elliptical function x^2 + 3y^2=b is orthogonal to the cubic y=3ax^3. I'm thinking they want me to prove if the functions are orthogonal when they intersect. If im correct that would just lead to; For the ellipse, 2x+6y(m1)=0, m1=-x/3y, when they intersect: m1=-x/3(3ax^3)=-1/9ax^2 Cubic, m2=9ax^2 m1xm2=[-1/9ax^2][9ax^2]=-1, Therefore they are orthogonal when they intersect. Am I right here? Is this even what the question was asking for?