Parabola General to standard form

In summary, the standard form of the given equation is (x-2)^2=-8(y-8) and the focus can be found at the vertex (2, 8).
  • #1
markwjak
1
0

Homework Statement


write the standard form of the equation
x^2-4x+8y+12=0
find the focus

Homework Equations


The Attempt at a Solution


i have it down to (x-2)^2=-8(y-8)
i'm not sure if you have to multiply the -8 on the right side of the equations by 4 since the focus is 1/4a
 
Last edited:
Physics news on Phys.org
  • #2
markwjak said:

Homework Statement


write the standard form of the equation
x^2-4x+8y+12=0
find the focus

Homework Equations





The Attempt at a Solution


i have it down to (x-2)^2=-8(y-8)
i'm not sure if you have to multiply the -8 on the right side of the equations by 4 since the focus is 1/4a

(x-2)^2=-8(y-8)

let x' = x-2
let y' = y-8

So, x^2 = -8y'
or y' = -(1/8)*x^2

This is it in standard form. To plot it, the vertex of the parabola will be (2, 8) and it will look like an upside down 'U'.
 
  • #3


Good work on getting the equation into standard form! To find the focus, we can use the formula for the focus of a parabola in standard form: (h, k + 1/4a). In this case, h = 2 and k = 8, so the focus is located at (2, 10). There is no need to multiply the -8 on the right side by 4. Keep in mind that the value of a in this case is actually -8, not 1/4a. Hope this helps!
 

1. What is the general form of a parabola?

The general form of a parabola is y = ax^2 + bx + c, where a is the coefficient of the squared term, b is the coefficient of the linear term, and c is the constant term.

2. What is the standard form of a parabola?

The standard form of a parabola is y = a(x-h)^2 + k, where a is the coefficient of the squared term, and (h,k) is the vertex of the parabola.

3. How do you convert a parabola from general form to standard form?

To convert a parabola from general form to standard form, you can use the process of completing the square. This involves manipulating the general form equation to get it in the form of y = a(x-h)^2 + k, where h and k can be determined from the original equation.

4. What do the coefficients a, b, and c represent in the general form of a parabola?

The coefficient a represents the direction and shape of the parabola, with positive values creating a "U" shape and negative values creating an upside down "U" shape. The coefficient b controls the horizontal position of the parabola, and c determines the vertical position.

5. How do I graph a parabola given in standard form?

To graph a parabola given in standard form, first plot the vertex at the point (h,k). Then, use the value of a to determine the direction and shape of the parabola. If a is positive, the parabola will open upwards, and if a is negative, it will open downwards. Finally, use the x-intercepts, which can be found by setting y equal to 0 and solving for x, to plot additional points and complete the graph.

Similar threads

Replies
44
Views
3K
  • Precalculus Mathematics Homework Help
Replies
5
Views
2K
  • Precalculus Mathematics Homework Help
Replies
4
Views
613
  • Precalculus Mathematics Homework Help
Replies
2
Views
1K
  • Precalculus Mathematics Homework Help
Replies
15
Views
3K
  • Precalculus Mathematics Homework Help
Replies
16
Views
1K
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
  • Precalculus Mathematics Homework Help
Replies
3
Views
2K
  • Precalculus Mathematics Homework Help
Replies
11
Views
515
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
Back
Top