# Thread: tangent lines of parabola that intersect on a certain point...

1. ## tangent lines of parabola that intersect on a certain point...

Consider the parabola

$\displaystyle y = \frac{x^2}{100}$

Find another point on the parabola with a tangent line that goes through (100,50).

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Can someone guide me through this please? It's due for homework tomorrow,

I've got as far as figuring out the tangent line is y=2x-150. Not sure what else to do. Thanks.

2. ## Re: tangent lines of parabola that intersect on a certain point...

Why does it say another point. There are two such points. Have you been given one of them?

3. ## Re: tangent lines of parabola that intersect on a certain point...

Originally Posted by Savior_Self
Consider the parabola
$\displaystyle y = \frac{x^2}{100}$
Find another point on the parabola with a tangent line that goes through (100,50).
You want to find points $\displaystyle (a,b)$ so that
$\displaystyle b=\frac{a^2}{100}~\&~\frac{b-50}{a-100}=\frac{a}{50}$