1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Contradiction in the definition and properties of the abs

  1. Feb 16, 2014 #1
    If the abs(a+b) = abs(a) + abs(b), so the abs(z) = abs(x+iy) = abs(x) + abs(iy) = abs(x) + i abs(y). However, the correct wouldn't be abs(z) = √[x²+y²] ?

    √[x²+y²] ≠ abs(x) + i abs(y) => abs(z) ≠ abs(z)

    It's no make sense. What there is of wrong with those definions?
  2. jcsd
  3. Feb 16, 2014 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    [tex]|a + b| \neq |a| + |b|[/tex]
    E.g. a = 2, b = -1
  4. Feb 16, 2014 #3


    Staff: Mentor

    As PeroK notes, this is incorrect. Since your hypothesis is false, any following work is meaningless.

    Also, the | key on the keyboard is usually used to write absolute values, as in |a + b|.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook