Answer
(a) Focus: $F(0,1)$
Directrix: $y=-1$
Focal~diameter: $4$
(b) See graph
Work Step by Step
Equation of a parabola with vertical axis: $x^2=4py$
$y=\frac{1}{4}x^2$
$x^2=4y$
$4p=4$
$p=1$
Focus: $F(0,p)=F(0,1)$
Directrix: $y=-p=-1$
Focal~diameter$=|4p|=4$
