Question

which is the directrix of a parabola with equation $x^2 = 4y$? $x = -1$ $y = -1$ $x = 1$ $y = 1$

Explanation:

Step1: Recall parabola standard form

For a parabola with equation \(x^2 = 4py\), the directrix is \(y=-p\).

Step2: Identify \(p\) from given equation

Given \(x^2 = 4y\), compare with \(x^2 = 4py\). So \(4p = 4\), which gives \(p = 1\).

Step3: Find directrix equation

Using the directrix formula \(y=-p\), substitute \(p = 1\). So directrix is \(y=-1\).

Answer:

\(y = -1\)