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#1 2008-02-04 08:23:42
- EMPhillips1989
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- Registered: 2008-01-21
- Posts: 40
please help
Let
and a,b,c be real numbers such that
and
show that
Last edited by EMPhillips1989 (2008-02-04 22:37:43)
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#2 2008-02-04 08:28:00
- mathsyperson
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- Registered: 2005-06-22
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Re: please help
Use the Triangle Inequality: |x+y| ≤ |x| + |y|.
Why did the vector cross the road?
It wanted to be normal.
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#3 2008-02-04 09:41:03
- EMPhillips1989
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- Registered: 2008-01-21
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Re: please help
When i use the triangle inequality i seem to get
when i surely want it to be for to be truecan you see where i've gone wrong????Last edited by EMPhillips1989 (2008-02-04 22:38:03)
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#4 2008-02-04 11:20:53
- mathsyperson
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- Registered: 2005-06-22
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Re: please help
You seem to have the right idea with that first line (trying to incorporate b's was a good idea), but it's not quite correct.
Use the triangle inequality on (a-b)+(b-c).
Why did the vector cross the road?
It wanted to be normal.
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#5 2008-02-04 22:36:52
- EMPhillips1989
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- Registered: 2008-01-21
- Posts: 40
Re: please help
so i tried adding them together this way and i seem to get the right answer im just not sure if my method is correct
i got
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#6 2008-02-05 00:51:05
- JaneFairfax
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- Registered: 2007-02-23
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Re: please help
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