Perhaps I haven't had enough coffee... is there a bug in the graph app relative to (for example) $x^3/(x+1)$ ? I don't see why there should be that parabolic looking bit in Q II.

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Answer 1 · 2016-01-26T13:10:27

No, the graph utility is working just fine.

I have a feeling that this is more of a math problem than an actual bug.

Try plotting that function on any other online graph calculator, you'll get the exact same curve.

For example, let's say that $x = 3$ . This will get you

$y = 3^3/(3 + 1) = 27/4$

But for

$y = 27/4 = x^3/(x+1)$

you also get

$4x^3 - 27x - 27 = 0$

This will produce

${ (x_1 = 3), (x_(2,3) = - 1.5) :}$

The vertex of that parabolic thing lies at $(-3/2, 27/4)$ , so I guess that makes sense after all.

Perhaps I haven't had enough coffee... is there a bug in the graph app relative to (for example) x^3/(x+1)x^3/(x+1)? I don't see why there should be that parabolic looking bit in Q II.