- #1
Agent M27
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Homework Statement
Let a & b be real numbers.
Prove that:
|a+b|<=|a|+|b|
Homework Equations
|x|=[tex]\sqrt{x^{2}}[/tex]
The Attempt at a Solution
|a+b|
=[tex]\sqrt{(a+b)^{2}}[/tex]
=[tex]\sqrt{(a^{2}+2ab+b^{2})}[/tex] <= [tex]\sqrt{a^{2}} + [tex]\sqrt{b^{2}}[/tex]
|a|=[tex]\sqrt{a^{2}}[/tex]
|b|=[tex]\sqrt{b^{2}}[/tex]
I feel like this is lacking in foundation, but I lack in the foundation of proofs involving absolute value. Thanks in advance for the assistance.
Joe
Sorry for the ugly formatting, tex is cumbersome sometimes.
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