Question: The tangent line to a circle may be defined as the line that intersects the circle in a single point, called the point of tangency.

The tangent line to a circle may be defined as the line that intersects the circle in a single point, called the point of tangency. See the figure.

Уд


If the equation of the circle is and the equation of the tangent line is, show that:

If the equation of the circle is x2 + y2 = r2 and the equation of the tangent line is y = mx + b, show that:

(a) r2 (1 + m2) = b2

The quadratic equation x2 + (mx + b) 2 = r2 has exactly one solution.

(b) The point of tangency is (-r2m/b, r2/b).

(c) The tangent line is perpendicular to the line containing the center of the circle and the point of tangency.

Step by Step Solution

3.57 Rating (157 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer
Step: 1 Unlock

a There is one solution if and only if the discriminant is zero b Using the quadratic ... View full answer

blur-text-image
Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock
Step: 3 Unlock

Students Have Also Explored These Related Precalculus Questions!