The focal length is found by equating the general expression for y

and our particular example:

So we have:

This gives p = 0.5.

So the focus will be at (0, 0.5) and the directrix is the line y = -0.5.

Our curve is as follows:

Note: Even though the sides look as though they become straight as x increases, in fact they do not. The sides of a parabola just get steeper and steeper (but are never vertical, either).