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

1 Answer
Mar 31, 2016

|-2+4i| =2sqrt(5)|2+4i|=25

Explanation:

The modulus of a complex number a+bia+bi is defined as

|a+bi| = sqrt(a^2+b^2)|a+bi|=a2+b2

(Note that this is the distance from the origin to the point (a,b)(a,b) on the complex plane)

In this case, that gives us

|-2+4i| = sqrt((-2)^2+4^2)|2+4i|=(2)2+42

=sqrt(4+16)=4+16

=sqrt(20)=20

=2sqrt(5)=25