1. Not finding help here? Sign up for a free 30min 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!

A proof question

  1. Nov 21, 2008 #1
  2. jcsd
  3. Nov 21, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Max[a, b] is "maximum of a and b" or simply the larger of the two numbers.

    You are asked to prove that max[a,b] = (1/2)(a+ b+ |a- b|)

    As always with absolute value problems, break it into to cases: a> b and a< b, and show that the two sides are the same in each of those cases.
  4. Nov 21, 2008 #3
    but there are variables
    even if i presume that a>b
    i cant develop into a formula
    i cant put it into the given expression
  5. Nov 21, 2008 #4
    the only thing i can do with the given expression
    is to split |a- b| into two cases
    a-b>0 ->a>b
    which gives me :
    (1/2)(a+ b+ a- b)=a

    a-b<0 a<b:
    (1/2)(a+ b-a+ b)=b

    i got a similar resolt but it didnt came from
    that in the i say "if a>b ..."
  6. Nov 21, 2008 #5


    User Avatar
    Science Advisor
    Homework Helper

    That's a proof, isn't it?

    What's wrong with that? :confused:

    (and why didn't you type out the question, and make it easier for every one?)
  7. Nov 21, 2008 #6
    in the first post i typed the question and added a link to the formula

    regarding the question:
    i did it correctly?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: A proof question
  1. Proof Question (Replies: 11)

  2. Proof question (Replies: 1)

  3. Proof question (Replies: 2)

  4. A proof question (Replies: 5)

  5. Proof Question (Replies: 3)