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

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Answer 1 · 2016-03-31T02:41:50

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

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

#|a+bi| = sqrt(a^2+b^2)#

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

In this case, that gives us

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

#=sqrt(4+16)#

#=sqrt(20)#

#=2sqrt(5)#