# Thread: Minimum distance from x axis

1. ## Minimum distance from x axis

Hi, could anyone please guide me through this question:
Find the minimum distance from a point on the positive
x-axis (a, 0) to the parabola y2 = 8x.

2. Originally Posted by ninja
Hi, could anyone please guide me through this question:
Find the minimum distance from a point on the positive x-axis (a, 0) to the parabola y2 = 8x.

A general point in the parabola is of the form $\displaystyle (\frac{y^2}{8},y)$, so use the formula for the distance between two points in the place to find the distance from $\displaystyle (a,0)$ to a point in the parabola as above, and then derivate wrt y to find citical points and etc.

Tonio

3. I tried it but doesn't work out for me. can you please explain a little more??

4. Originally Posted by ninja
I tried it but doesn't work out for me. can you please explain a little more??
Better yet, can you please show all the details of what you tried so that your trouble can be identified.