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mathematics
bound/unbounded
Mar 08, 2007 23:36
1. What is an example of f + g + h being bounded while f, g, and h being unbounded (
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Comments 8
pyrop
March 9 2007, 04:45:21 UTC
There's nothing stopping you from defining h in the 2nd problem to be some arbitrary finite number at x=0.
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bewlay_brother
March 9 2007, 04:53:46 UTC
Indeed, the functions need only be unbounded, not continuous.
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polynomial
March 9 2007, 05:14:02 UTC
Maybe I'm confused, but for #1, what about f = 2x, g = -x, and h = -x?
For #2, you can fix things misbehaving at 0 with exponential functions, I think. For example, f = g = 2^x, g = 2^{-2x}?
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squeegibo
March 9 2007, 14:50:10 UTC
1. As
polynomial
said, f = 2x, g = -x, h = -x is a solution.
2. f = e^2x, g = e^-x, h = e^-x should work.
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taral
March 9 2007, 18:32:18 UTC
Cute transform. I missed the second part of his question.
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bewlay_brother
March 9 2007, 18:41:44 UTC
Remember kids, the exponential function is a group homomorphism between the additive and multiplicative groups of the reals!
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polynomial
March 10 2007, 01:05:03 UTC
Remember kids, the exponential
There's only one?
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For #2, you can fix things misbehaving at 0 with exponential functions, I think. For example, f = g = 2^x, g = 2^{-2x}?
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2. f = e^2x, g = e^-x, h = e^-x should work.
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There's only one?
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