Thread: Find equation of the parabola

If the axis is parallel to x axis, Latus Rectum = 1 and passing through (3,1) and (-5,5)

Help please. No idea. The axis parallel to x axis made it confusing.

Hello reiward

Originally Posted by reiward

If the axis is parallel to x axis, Latus Rectum = 1 and passing through (3,1) and (-5,5)

Help please. No idea. The axis parallel to x axis made it confusing.

The 'standard' parabola with axis parallel to the -axis has equation

and if we move the vertex from the origin to the point , this equation becomes:

Now the latus rectum has length . So here , and the equation now becomes:

Plug in the values of and at the two points you're given:

So the equation is:

which can be re-written as:

if you like.

Grandad