Which of the following has a graph that is wider than the graph of y=x^2+2? a. y=3x^2+3 b.y=0.5x^2+1 c.y=-4x^2-1 d.y=4x^2+1.

I know its not b. And im leaning for a. but i dont understand this yet. just starting quadratic equations and such.

Question

Which of the following has a graph that is wider than the graph of y=x^2+2? a. y=3x^2+3 b.y=0.5x^2+1 c.y=-4x^2-1 d.y=4x^2+1.  

I know its not b. And im leaning for a. but i dont understand this yet. just starting quadratic equations and such.

phi · Answer

if you have  y = a x^2 + b
you can ignore the b when trying to figure out how "wide" or how narrow the graph is.

start with
y= x^2     (rather than x^2 + 2, because we can ignore the +2)
that equation says as that whatever x is, y is x*x
|dw:1424893847854:dw|
the graph looks like a smile