When I enter a function of the form f(x) = a*x^n +b*x^2+c*x+d
the gradient function f'(x) is only graphed for x>= 0 for some reason.
i think that x^n is internaly defined with logs and so x must be >0
at that moment you can try sgn(x)*abs(x)^n when n is odd number
f'(x) is only graphed for x> 0 because of the domain of the function ln(x).
But the expression of f'(x) is not correct...
It seems that in version 3, functions are defined differently. In version 2.7, GeoGebra had no problem graphing the gradient function of f(x) = ax^n+bx for all real x. Does anyone know why things were redefined?
Looks fine to me... it's just not simplified :)
There's another thread somewhere that explains about the change in 3.0 but I can't find it (searching for x^(1/3) doesn't seem to work in the forums)
When n = 2, f(x) = ax^n+bx has a linear gradient function with a domain of all real x. However, GeoGebra only shows the gradient function for a domain of x>0. This is incorrect.
no it's not, because the definiton of a^n for general n is e^(nloga)
if you define f(x)=polynomial[a x^n+b x^2+c x+d] derivate work correctly for integer "n" and all real x
Thanks. Now it works. I never had to do that with version 2.7.
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