Question

Question about parabolas =)

Answer 1

I know that the general form of a quadratic equation is f(x) = a(x - h)^2 + k. I know K controls the vertical movement of the parabola, H controls the horizontal movement, and A controls if it opens up or down and how wide it is. My question is, how do you know how wide to make the parabola? For example, f(x) = 2(x - 5)2 - 3, how do I know how wide 2 is?

Answer 2

mmm
the way I think of it is that for the parent graph, a = 1
from the vertex it'll be over 1 up 1, over another 1 up another 3, over another 1 up another 5 etc
so then when a = 2
from vertex it'll be over 1 up 2, over another 1 up another 6, over another 1 up another 10 ,etc.

(my way of thinking of it, may not apply to some parabolas, best if you'd ask for another opinion?) :)

Answer 3

Okay, I see what you're talking about. That makes sense. Thanks!

Answer 4

glad I could help :)