Question

How do you find `abs(2 - 4i)`?

Answer 1

`2sqrt5`

Explanation:

Given a complex number z = x + iy , then it's magnitude is found as follows

`color(red)(|bar(ul(color(white)(a/a)color(black)(r=|z|=|x+iy|=sqrt(x^2+y^2))color(white)(a/a)|)))`

here x = 2 and y = -4

`rArr|2-4i|=sqrt(2^2+(-4)^2)=sqrt20=2sqrt5`