Talk:Chain rule

In line with the following,
 * $$(f \circ g)' = (f' \circ g) . g' \,$$,

I would write for pedagogical reasons:


 * $$ z(y(x)) \leftrightarrow z\circ y(x), $$

and that
 * $$ (z \circ y)' = (z' \circ y) . y' \,$$

reads in Leibniz (traditional) notation,
 * $$\frac{\mathrm{d} z(y(x))}{\mathrm{d} x} = \frac{\mathrm{d} z(y)}{\mathrm{d} y} \cdot \frac{\mathrm{d} y(x)}{ \mathrm{d} x} . \, $$.

What do you think? --Paul Wormer 09:50, 8 November 2008 (UTC)