Graphic not showing correnctly on this specific formula

[Paul_Duchesneau]

Something’s not working the way it seems like it should.

When I type the following formulas
{
f(x) = e^rx
g(x) = f’’(x)-2f’(x)-3f(x)
}

I saw wrongs values on the graphic, starting at x=10 its very clear that the function return values that are wrong, it should be 0 for all values of x, when r=3, actually g(x) is equal to zero when r = -1 and r=3 (when r=-1 the values of the graphic are correct)

here are some screenshots

[Jay (Jay Chow)]

Hey Paul!

This is caused by a floating point error. Basically, your function starts off looking fine until the numbers get really big and in turn, the errors do as well. So instead of cencelling to zero it gets wild.

You can see the same thing happening with something simpler like 3e^x-2e^x-e^x. In this case you’ll see it happen out near 30.