# Distance between two points in polar coordinate system.

sotnet
Guys,

Any ideas on how to calculate distance between two points in Polar coordinate system without converting their coordinates to Cartesian?

Ps. I know that if I converted from Polar (r, t) to Cartesian (x, y) by x = r.cos(t), y = r.sin(t), then the distance between two points would be d = sqrt((x1 - x2)^2 + (y1 - y2)^2).

Thanks,
Steve

lzkelley
You use the law of cosines.
Construct a triangle with vertices at the origin, and the two points.
Its a cool trick, but makes for a huge pain in the ass for calculating inverse square laws etc. in polar/spherical.

I can elaborate if the setup doesn't make sense.