Calculate cubic roots with W|A?

Questions
1

Goodmorning everyone! !
I have a doubt . Because Wolfram returns as the domain of the cube root only numbers greater than zero ?
Thanks . David

2

Hi,

that’s a popular question. Look at this:

FunctionDomain[x^(1/3), x]
(*x >= 0*)

and

FunctionDomain[Surd[x, 3], x]
True

The main point is that there is more than one result for the cubic root. Surd returns the real valued solution, and Power returns the principal one.

Cheers,

M

3

Ok, but analysis of the following function : f ( x ) = ( logx ) ^ 1/3 wolframe return domain as x greater than 1, while the correct value for the domain x is greater than zero . This means that the wolframe graphs can be wrong ? Thanks . David
Ps sorry for My English. :slight_smile:

4

Thanks of help I understand is solved by placing f(x)=x^2 cbrt (logx)
:wink:

5

You are right :

f[x_] := Log[x]^(1/3)

Plot[f[x], {x, 0, 5}]

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