(properties of mulitiplication of inequalities)
 
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[[Category:MA375Spring2009Walther|inequality multiplication]]
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There is a property of inequalities that states: <br/>
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if c is some positive number and a < b, then ac < bc  <br/>
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if c is some negative number and a < b, then ac > bc  <br/>
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From this property we can prove inequalities such as the following:
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If a<b and c<d, where a, b, c, and d are positive numbers then ac<bd must be true.

Latest revision as of 05:44, 29 January 2009

Is there a formal way of saying a<b and c<d implies ac<bd, like a theorem from algebra or something? Just wondering because I used it for my inductive step.

I believe the way you wrote it should be fine for the proof.

There is a property of inequalities that states:

if c is some positive number and a < b, then ac < bc
if c is some negative number and a < b, then ac > bc

From this property we can prove inequalities such as the following:

If a<b and c<d, where a, b, c, and d are positive numbers then ac<bd must be true.

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