alexhuntley / Plots

A graph plotting app for GNOME
GNU General Public License v3.0
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Implicit equation for ellipse yields hyperbola (and vice versa) #109

Closed lkstl closed 1 year ago

lkstl commented 1 year ago

Bildschirmfoto vom 2023-01-17 14-51-48

The implicit equation $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ is correctly plotted as an ellipse. Subtracting $\frac{x^2}{a^2}$ should not change the plot, however, $\frac{y^{2}}{b^{2}}=1-\frac{x^{2}}{a^{2}}$ is plotted as a hyperbola. For good measure I have thrown in further transformations of the equation (making it an explicit equation); they are displayed correctly.

Vice versa, the equation $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ is correctly plotted as a hyperbola but the transformed equation $\frac{x^2}{a^2}=1+\frac{y^2}{b^2}$ becomes an ellipse (not shown in image).

alexhuntley commented 1 year ago

Thanks for spotting this!