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#1 2007-12-22 06:46:13

tony123
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Registered: 2007-08-03
Posts: 189

solve inequality

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#2 2007-12-22 07:35:23

mathsyperson
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Registered: 2005-06-22
Posts: 4,900

Re: solve inequality


Why did the vector cross the road?
It wanted to be normal.

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#3 2007-12-22 22:48:56

tony123
Member
Registered: 2007-08-03
Posts: 189

Re: solve inequality

Tank you mathsyperson but
let x=6/10

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#4 2007-12-22 23:57:24

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: solve inequality

Sorry, I'm not sure what you're getting at.
6/10 is a solution and is in my solution set, so there's no contradiction.

If you're hinting at a more elegant method of reaching the answer, I'm afraid I don't get that either.


Why did the vector cross the road?
It wanted to be normal.

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#5 2007-12-23 00:56:10

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: solve inequality

Perhaps he’s hinting that your solution isn’t wholly correct. x = 6⁄10 is NOT a solution. Also, you can’t have x = 1. What is logarithm to base 1, anyway?

Anyway, log[sub]x[/sub] where x < 1 problematic. If x < 1, then you actually have log[sub]x[/sub]y > 0 when y < 1 and log[sub]x[/sub]y < 0 when y > 1. With this in mind, I think you’ll find that not only

is invalid but also

is a solution set as well.

Last edited by JaneFairfax (2007-12-23 01:00:39)


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#6 2007-12-23 01:42:59

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: solve inequality

Ah, fair enough. I made too many assumptions in the first step.


Why did the vector cross the road?
It wanted to be normal.

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