Question

What is the focus of the parabola `x=y^2 + 4`?

Answer 1

This is a parabola 'on its side', opening to the right, rather than the `'y=x^2+b'` shape we're more used to. In this case, the focus is at `y=0`, so it's just `x=4`.

Explanation:

The focus of this parabola will be at `y=0`. If we substitute this in to the equation, we get:

`x=y^2+4 to x=0^2+4 to x=4`