Why The function APP failled to find an extremum in this case

[dg1969]

Good morning dear "Primers",

Can you explain why the function App failed if i ask for an extremum of \(f(x)\)?
\(f(x)=\frac{1}{9} \cdot (84\cdot x e^{-3\cdot x}-2 e^{-3\cdot x}+2)\)

Code:

f(x):=1/9*(84*x*e^(-3*x)-2*e^(-3*x)+2)

1) I create \(f(x)\) in CAS side. Have you notice the Latex command ? Did you know that ? !
CTRL+C CTRL+V to paste on these post !!! ;o) Thank's to M. PARISSE !


2) I choose F1(X)=f(X)

Here notice that the EVAL softKey do nothing !? Why ?

3)Plot and choose "EXTREMUM"


4) Can't find an extremum !!
[/code]

Thank's for reading.

Didier