Graphing Ellipses: How to Change Formats

In summary, the conversation is about graphing an ellipse and the confusion regarding its equation. The equation given is in the form of \(\displaystyle\frac{(x+2)^2}{5} + \frac{2(y-1)^2}{1} = 1\), which can be rearranged to match the standard form for an ellipse. The center point of the ellipse is at \((-2,1)\).
  • #1
veronica1999
61
0
How do I graph this ellipse?

It doesn't seem to be in the right form.

(x+2)^2 /5 + 2 (y-1)^2 = 1

I don't know what to do with the 2 in front of the (y-1)^2

Doesn't an ellipse have to be x^2/a^2 + y^2/b^2 = 1
 
Mathematics news on Phys.org
  • #2
veronica1999 said:
How do I graph this ellipse?

It doesn't seem to be in the right form.

(x+2)^2 /5 + 2 (y-1)^2 = 1

I don't know what to do with the 2 in front of the (y-1)^2

Doesn't an ellipse have to be x^2/a^2 + y^2/b^2 = 1

Hi veronica1999, :)

Yes, an ellipse has its equation as, \(\displaystyle\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1\) if its major and minor axes coincides with the \(x\) and \(y\) axes of the Cartesian coordinate system. In this case the center point of the ellipse is at the origin. However a ellipse with its center point at, \((x_{0},y_{0})\) has an equation of the form,

\[\frac{(x-x_{0})^2}{a^2} + \frac{(y-y_{0})^2}{b^2} = 1\]

In your case the ellipse is centered at, \((-2,1)\). Now you should be able to draw your ellipse. :)

Kind Regards,
Sudharaka.
 
  • #3
Thanks.
But I am still not sure what to do with the 2 in front of the (y-1)^2.
Could it have been a mistype meaning (y-1)^2/2 instead of 2(y-1)^2?
 
  • #4
veronica1999 said:
Thanks.
But I am still not sure what to do with the 2 in front of the (y-1)^2.
Could it have been a mistype meaning (y-1)^2/2 instead of 2(y-1)^2?

Of course not. You can rearrange the equation by taking that \(2\) to the denominator like this,

\[\frac{(x+2)^2}{5} + \frac{(y-1)^2}{\frac{1}{2}} = 1\]

Is it clear to you now? :)
 
  • #5
Yes!;)

Thank you!
 
  • #6
veronica1999 said:
Yes!;)

Thank you!

You are welcome. I am glad to be of any help. :)
 

1. How do I convert an equation of an ellipse from standard form to general form?

To convert an equation of an ellipse from standard form to general form, follow these steps:
1. Rewrite the equation in the form x^2/a^2 + y^2/b^2 = 1
2. Factor out the common factor from the numerator of both fractions, if any.
3. Multiply both sides of the equation by a^2 and b^2.
4. Simplify and rearrange to get the equation in the form Ax^2 + By^2 + Cx + Dy + E = 0, where A, B, C, D, and E are constants.

2. How do I graph an ellipse using the general form of the equation?

To graph an ellipse using the general form of the equation, follow these steps:
1. Rewrite the equation in the form Ax^2 + By^2 + Cx + Dy + E = 0.
2. Find the center of the ellipse by calculating (-C/2A, -D/2B).
3. Find the lengths of the major and minor axes by solving for x and y when Ax^2 + Cx + E = 0 and By^2 + Dy + E = 0, respectively.
4. Plot the center and the endpoints of the major and minor axes on the coordinate plane.
5. Sketch the ellipse by connecting the points on the axes with a curved line.

3. How do I convert an equation of an ellipse from general form to standard form?

To convert an equation of an ellipse from general form to standard form, follow these steps:
1. Rewrite the equation in the form Ax^2 + By^2 + Cx + Dy + E = 0.
2. Complete the square for both x and y terms by adding and subtracting the appropriate constants.
3. Factor out the common factor from the x and y terms, if any.
4. Simplify and rearrange to get the equation in the form (x-h)^2/a^2 + (y-k)^2/b^2 = 1, where (h,k) is the center of the ellipse and a and b are the lengths of the major and minor axes, respectively.

4. How do I find the foci of an ellipse given its equation?

To find the foci of an ellipse given its equation, follow these steps:
1. Rewrite the equation in the form Ax^2 + By^2 + Cx + Dy + E = 0.
2. Calculate c = √(a^2 - b^2), where a and b are the lengths of the major and minor axes, respectively.
3. The foci of the ellipse are located at (h±c, k), where (h,k) is the center of the ellipse.

5. Can an ellipse have a negative radius?

No, an ellipse cannot have a negative radius. The radius of an ellipse is always positive, and it is the distance from the center of the ellipse to any point on its perimeter. Therefore, the equation of an ellipse cannot have a negative value for a or b, which are the lengths of the major and minor axes, respectively.

Similar threads

Replies
4
Views
831
Replies
6
Views
1K
  • General Math
Replies
3
Views
1K
Replies
2
Views
1K
Replies
9
Views
830
Replies
1
Views
2K
Replies
5
Views
954
Replies
23
Views
1K
  • General Math
Replies
7
Views
958
  • General Math
Replies
5
Views
1K
Back
Top