Thread: L is Tangent to C?

Hey,

I must be an idiot because the answer to this is probably simple.

Anywho.

Circle has equation X^2+y^2+4x-8y+10=0

So Center is (-2,4) and Radius is Route 10.

Now L has an equation X-3y+4=0

All I have to do is show that L is a tangent to C.

Originally Posted by StephenPoco

Hey,

I must be an idiot because the answer to this is probably simple.

Anywho.

Circle has equation X^2+y^2+4x-8y+10=0

So Center is (-2,4) and Radius is Route 10.

Now L has an equation X-3y+4=0

All I have to do is show that L is a tangent to C.

If L is a tangent to C then they must have a common point, say .

Common point means:


Now solve these two equations simultaneously. Then will satisfy both and be the required common point.