Definition:Relative Error/Also defined as

Definition
Let $x_0$ be an approximation to a (true) value $x$.

The relative error of $x_0$ can also be defined as:


 * $\delta x \approx \dfrac {\Delta x} {x_0}$

where:
 * $\Delta x$ denotes the absolute error of $x_0$
 * $\approx$ indicates that the value is but approximate.

This can be particularly useful when the true value $x$ can only be speculated.