How do you find #abs( -5 - 4i )#?

1 Answer
Sep 6, 2016

#sqrt41#

Explanation:

Given a complex number z = x + yi , then it's #color(blue)"modulus ( magnitude )"# is found using Pythagoras' theorem.

#color(orange)"Reminder " color(red)(|bar(ul(color(white)(a/a)color(black)(|x+yi|=sqrt(x^2+y^2))color(white)(a/a)|)))#

here x = - 5 and y = -4

#|-5-4i|=sqrt((-5)^2+(-4)^2)=sqrt(25+16)=sqrt41≈6.403" units"#