Question

T he equation for a parabola with directrix y = –p and focus (0, p) is:
https://media.glynlyon.com/g_alg02_ccss_2013/8/equation_parabola.gif
What is the line of symmetry?

x-axis

y-axis

x = p

x = -p

Answer 1

y = .....x^2 is an upward parabola which has y-axis is the line of symmetry.

Answer 2

y-axis was my 1st answer but it was incorrect

Answer 3

so, it's over my head. I am sorry for being helpless. :) Let tag other @SithsAndGiggles

Answer 4

The directrix is horizontal, so the axis of symmetry (which is always perpendicular to the directrix) is vertical. Any vertical line has the form \(x=\cdots\).

The axis of symmetry must pass through the vertex and focus. If this axis is the line \(x=\cdots\), then \(\cdots\) is the x-coordinate of any point on this line.

You know one point that lies on the line. What's its x-coordinate?

Answer 5

x=p

Answer 6

No, what's the x-coordinate of (0,p)?

Answer 7

sorry about that, my mouse wasn't working so I couldn't send my message. x-axis @SithsAndGiggles

Answer 8

No, it's the y-axis. The y-axis has the equation \(x=0\).

Answer 9

It says it's incorrect

Answer 10

can you copy the page and paste it here??