Using sliders to change the coefficients of a polar equation.

This program draws a polar equation. Each iteration of the draw loop it draws points in a 360 degree arc
while automatically changing the radius using the polar equation
From 11th grade math, you know that polar equations are functions that define the radius, r,
as a function of the angle, θ. Also, you know that the radius and angle can be converted to
Cartesian coordinates, (x, y), using the equations: x=r*cos(θ) y=r*sin(θ)

This program graphs the polar equation: r=a*cos(b*θ) + c*sin(d*θ)