Blake Andrews
New member
- Joined
- Feb 12, 2020
- Messages
- 11
Hi,
I have a question asking to write a set of parametric quations for the following parabola:
x2=-36y
I used:
x2=-4ay
x2=-4(9)y, so a=9
The parabola is in the form x2=-4ay so it is concave down with parametric co-ordinates of
x=2at and
y=-at2
So x=2(9)t
=18t
and
y=-9t2
My textbook is telling me the answer is x=-18t, y=-9t2, which makes sense to me as it's concave down but i can't see where i went wrong in the method i used.
I have a question asking to write a set of parametric quations for the following parabola:
x2=-36y
I used:
x2=-4ay
x2=-4(9)y, so a=9
The parabola is in the form x2=-4ay so it is concave down with parametric co-ordinates of
x=2at and
y=-at2
So x=2(9)t
=18t
and
y=-9t2
My textbook is telling me the answer is x=-18t, y=-9t2, which makes sense to me as it's concave down but i can't see where i went wrong in the method i used.