How do you plot $x = y^2 - 6$ on a graphing calculator?

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I have a graphing calculator app (Graphing Calculator+) that only allows me to enter $x$ as a variable, but I need to graph $x = y^2 - 6$.

I haven't used a graphing calculator in awhile. Is this normal? If it is, is there some kind of a trick to graphing this equation?

Your help would be appreciated.

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3 Answers

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To plot $x=f(y)$ without having to mentally flip across the $y=x$ diagonal, you could plot $y = -f(x)$, then turn the calculator 90° counterclockwise. In your case, plot $y=-(x^2-6)$.

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You may :

• graph $y=x^2-6$ and mentally reverse the $x$ and $y$ axis
• graph $y=\sqrt{x+6}$ and $y=-\sqrt{x+6}$ obtaining the two required branches
• use the parametric method $x=t^2-6,y=t$ proposed by The Chaz! (probably the best solution if it works...)

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GeoGebra allows entry directly in that form, eg

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