While doing an experiment I've came upon the need to calculate the error of my value that was calculated using observed values with known observational error. While I know how to calculate the error for expressions with two observed values:
$$ \frac{\mathrm{d}F}{F}=\sqrt{\left(\frac{\mathrm{d}x}{x}\right)^2+\left(\frac{\mathrm{d}y}{y}\right)^2} \quad \text{for } F=x y \text{ or } F=\frac{x}{y} $$
Is there a formula for more complex expressions, like $F=xyz$, of $F=\frac{xy}{z}$ and such, or am I forced to calculate the value of $x y$ and its error and then use it with $z$ and its error?