Topics: Numerical Analysis
The relative error normalises the error to the true value. It’s given by:
…where is the exact value we’re trying to approximate to, while is our last approximation.
Compare the absolute error.
If the Exact Value isn't Known
If the exact value isn’t known (i.e. we’re using a numerical method to find it), then is the last approximation we got, and the penultimate one.
This can only be done with convergent numerical methods, since this ensures our last approximation is better than the one before.
Relative Porcentual Error
The relative error can also be given the in a percentage (%):