Formulas for arc tangent to circle with known end point.

[mrk]

I am trying to understand some of the basic formulas needed to calculate my own tool paths. Does anyone around here have advice on a book, website, or simply would like to help answer some math questions?

Arc Start Point = x1, y1
Circle1 = x2, y2, r1
Arc Radius = r2
Arc End Point (point on circle1 such that arc is tangent) = x3, y3

What does the math formula for calculation of x3, y3 when the other values are known?

[Jarwalcot]

You might try searching here: http://www.efunda.com/math/trig_func..._functions.cfm