Question

How do you find `abs( -1 + 2i )`?

Answer 1

`sqrt5`

Explanation:

Given a complex number z = x + iy then the magnitude is

|z| = |x +iy| `= sqrt( x^2 + y^2)`

here x = -1 and y = 2

hence |-1 + 2i| `= sqrt((-1)^2 + 2^2) = sqrt5`