Gottfried thanks for making this derivation work!
this is just applied multiplication rule \( (f*g)'=f'*g+f*g' \) together with chain rule \( (f\circ g)'=(f'\circ g)*g' \).
Quote:I cannot follow the formal derivative at the moment,
Quote:Ok, we have \( W(x)e^{W(x)}=x \). Take the derivative:
\( W'(x)e^{W(x)}+W(x)e^{W(x)}W'(x)=1 \)
this is just applied multiplication rule \( (f*g)'=f'*g+f*g' \) together with chain rule \( (f\circ g)'=(f'\circ g)*g' \).