Hi Ben.

That is certainly a messy equation when you try to rearrange for y. Personally I would change coordinates.

Changing to polar: , we get.

Maybe it's easier to work with from here.

Results 1 to 6 of 6

- September 11th 2012, 04:42 AM #1

- Joined
- Sep 2012
- From
- Norn Iron
- Posts
- 3

## xy(x^2 - y^2) = C

I wanted to plot for C=840 but realised I couldn't isolate either x or y

I went to quickmath.com and entered the general equation and got...

Solve Equation :: QuickMath.com - Automatic Math Solutions

This returned 3 equations for calculating y; 2 complex and 1 real.

I know that for (7, 3), (7, 5) and (8, 7) are co-ordinates on the curve.

I cannot get these results by plugging in C=840, x=7 to the equations returned by quickmath.com.

Am I doing something wrong?

Thx

Ben

- September 11th 2012, 04:59 AM #2

- Joined
- Jun 2009
- Posts
- 220
- Thanks
- 1

- September 11th 2012, 07:36 AM #3

- Joined
- Sep 2012
- From
- Norn Iron
- Posts
- 3

- September 11th 2012, 10:20 AM #4

- Joined
- Dec 2007
- From
- Ottawa, Canada
- Posts
- 3,184
- Thanks
- 80

- September 11th 2012, 11:04 AM #5

- Joined
- Sep 2012
- From
- Norn Iron
- Posts
- 3

- September 11th 2012, 11:42 AM #6

- Joined
- Dec 2007
- From
- Ottawa, Canada
- Posts
- 3,184
- Thanks
- 80