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- Aug 9th 2010, 05:32 PMtempinsProof of how multiplying a positive and negative constant changes the sup and inf
Solved

- Aug 9th 2010, 06:23 PMVlasev
For your second question, it's more along those lines. Let and where . Let a be a positive number. Then is a negative number.

by the rules of ">".

Hence now you have that and

Try an example: the interval for example. , . When you take [LaTeX ERROR: Convert failed] , you get and it should be clear. - Aug 10th 2010, 04:25 AMHallsofIvy
Please do NOT erase a post just because you do not need it any more. New people looking at the thread can still learn something from it.

- Aug 10th 2010, 04:51 AMVlasev
The question was along the lines of:

If is a set and and if is a constant, then let denote the set .

Then if and , prove:

If then and .

If then and .