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Calculus/Basic inequality

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Expert: - 10/11/2008


Question
prove that //a/-/b//is greater than or equal/a-b/

note:[/]mark means absolute

Answer
Questioner:   ahmed
Category:  Calculus
Private:  No
 
Subject:  caculas
Question:  prove that |a| - |b| is greater than or equal  |a-b|

note:[/]mark means absolute
.............................
Hi, Ahmed,

You have to prove this is true for all 'a' and all 'b'.  For example,

a = 5,  b = -3.

|a| - |b| = |5| - |-3| = 5 - 3 = 2, which is greater than

| a - b | = | 5 - (-3) | = | 5 + 3 | = | 8 | = 8

Oops -- it isn't. Something went wrong here.

Look up the triangle inequality.

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