# How do you find the absolute value of -4+i?

Nov 15, 2016

Please see the explanation for how one computes the magnitude of a complex number.

#### Explanation:

I think that you mean magnitude.

Given a complex number of the form $a + b i$

$| a + b i |$

means magnitude; not absolute value and it is computed as follows:

$| a + b i | = \sqrt{{a}^{2} + {b}^{2}}$

$\therefore$

$| - 4 + i | = \sqrt{{\left(- 4\right)}^{2} + {1}^{2}}$

$| - 4 + i | = \sqrt{17}$