Tangent lines are drawn from a given external point to a circle. The equation is found by joining their points of contact
William Briggs, G.H. Bryan The Elements of Coordinate Geomentry Part 1. The Equations and Properties of the right line and circle (, : University Correspondence College Press Warehouse, ) 153
3143×3109, 468.0 KiB
1024×1012, 31.8 KiB
640×633, 18.0 KiB
320×316, 7.8 KiB