La Derivada
Derivada simple
\[
y = f(s) = 2x^4 + 3x^2 + 6x +1
\Rightarrow \frac{dy}{dx} = 8x^3 + 6x + 6
\]
Regla de la cadena
\[
z = f(x(t), y(t)) \longrightarrow
\frac{dz}{dt} = \frac{\partial f}{\partial x}\frac{dx}{dt} + \frac{\partial f}{\partial y}\frac{dy}{dt}
\]
Gradiente de una función
\[
grad(\phi) = \frac{\partial \phi}{\partial x} \overrightarrow{i} +
\frac{\partial \phi}{\partial y} \overrightarrow{j} +
\frac{\partial \phi}{\partial z} \overrightarrow{k}
\]