# Microsoft Office Application Help - Excel Help forum > Excel Charting & Pivots >  > [SOLVED] Graphing ellipse equation

## Scott Smith

How do you graph an ellipse euation in the excel?

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## Jon Peltier

The easiest way is to calculate X and Y parametrically. I used the angle
theta, which I varied from 0 to 360 degrees. I can use cos(theta) and
sin(theta) to get the coordinates of a circle of radius 1. If my ellipse
formula is

(x/a)^2 + (y/b)^2 = 1

then my points are simply related to the above by factors of a and b.

So put angles in column A (0 to 360 in increments of 15 worked adequately
well in my example: this filled A3:A27). Put the values for a and b into
cells B1 and C1. Use this formula in B3 for X:

=B$1*COS(A3*PI()/180)

and use this formula in C3 for Y:

=C$1*SIN(A3*PI()/180)

Fill these formulas down to row 27. Select B3:C27 and create an XY chart
with connecting lines. Then adjust the height, width, and axis scales of the
chart so the grid is square
(http://peltiertech.com/Excel/Charts/SquareGrid.html), and you'll see your
ellipse.

- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services - Tutorials and Custom Solutions -
http://PeltierTech.com/
2006 Excel User Conference, 19-21 April, Atlantic City, NJ
http://peltiertech.com/Excel/ExcelUserConf06.html
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"Scott Smith" <Scott Smith@discussions.microsoft.com> wrote in message
news:25824BC3-4769-4C12-AE45-1979BAECA8C8@microsoft.com...
> How do you graph an ellipse euation in the excel?

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## safaval1

Thank you. This is awesome.

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