@phi Can you help me again with math derivatives? I asked last week and somebody helped but I still don't get it and failed the test. will you teach me?
1. Derive the equation of the parabola with a focus at (4, −7) and a directrix of y = −15. Put the equation in standard form.

Question

@phi  Can you help me again with math derivatives? I asked last week and somebody helped but I still don't get it and failed the test. will you teach me?
1. Derive the equation of the parabola with a focus at (4, −7) and a directrix of y = −15. Put the equation in standard form.

phi · Answer

to do these questions, you should find the vertex.
the vertex is exactly between the focus and the directrix.

The first step is plot the focus and the directrix, just to see what is what.
then find the point mid way between them.