Math for Specialized Program

Math for Specialized Program

By Titik Purwanti

The Equation Tangent Line to A Circle

• Given the two point that through the line and the circle

• Given the gradient of tangent line

The Equation of the tangent line to circle if given a point that through it.

Let (x₁, y₁) is point that through the line and the circle. then the equation of the tangen line to circle that has center (a, b) and radius r is

(x-a)(x₁-a)+(y-b)(y₁-b)=r²

The Equation of the tangent line to circle if given gradient of the tangent line

Let m is gradient of the tangent line to circle that has center (a, b) and radius r. the equation of the tangent line is
(y-b)=m(x-a) $\pm r\sqrt{m^2+1}$