Uploaded Jan 19, 2014
The purple curve has polar equation r=f(θ).
A lies on this curve, and B is a point at the intersection of the tangent at A with the line perpendicular to OA.
The red curve is the locus of B
The grey curve is the curve r=g(θ) rotated by the quantity on the slider.
What function g() will rotate to lie on top of the red curve?