Ack, such a simple question, but I haven't worked with conic sections in years. Can anyone suggest an elegant way to show that [tex]x=f*Sin(wt+\theta)[/tex] [tex]y=g*Sin(wt+\phi)[/tex] is an ellipse? I've tried using a rotation matrix on standard parametric ellipse equations and then solving for the angle of rotation and the axes sizes in terms of the variables but it seems messy. Then I tried getting it to fit the general equation but I'm not sure how that would work. However, a simpler method is eluding me. Any help?