Did I do this correctly?

[happysmiler07]

· Suppose a parabola has vertex (2,3) and it passes through the point (4,1). Describe the steps you would take to find the formula for the parabola.

The general equation for a parabola with vertex (h,k) provided is:

y=a(x-h)^2+k

so y=a(x-2)^2+3
now we use the points values for x and y.

4=a(1-2)^2-3
4=1a-3
1=1a
1=a

The equation is:

y=x^2-4x-3
y=x^2-4x+4

I feel like I am missing something, so clarification would be great. Thanks.

 

[Quaid]

· Suppose a parabola has vertex (2,3) and it passes through the point

(4,1). Describe the steps you would take to find the formula for the parabola.

The general equation for a parabola with vertex (h,k) provided is:

y=a(x-h)^2+k

so y=a(x-2)^2+3
now we use the points values for x and y.

4=a(1-2)^2-3

Hi happysmiler:

You set up the equation with x and y properly, but you swapped the values 4 and 1, when substituting for x and y.

Also, how did the +3 turn into -3 (typo, maybe)?

You need to solve this for a:

1 = a(4 - 2)^2 + 3

Cheers

 

[happysmiler07]

Hi happysmiler:

You set up the equation with x and y properly, but you swapped the values 4 and 1, when substituting for x and y.

Also, how did the +3 turn into -3 (typo, maybe)?

You need to solve this for a:

1 = a(4 - 2)^2 + 3

Cheers

ahhh okay...