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Topic: easiest way to solve rational polynomial inequality p(x)/q(x) > 0 is
by solving p(x)q(x) > 0

Replies: 12   Last Post: Aug 23, 2013 4:22 PM

 Messages: [ Previous | Next ]
 vrut25@gmail.com Posts: 5 Registered: 12/1/12
Re: Solving rational polynomials
Posted: Aug 17, 2013 6:06 PM

On Saturday, August 17, 2013 1:26:18 AM UTC-7, Virgil wrote:
>
> Kobu <kobu.selva@gmail.com> wrote:
>
>
>

> > Thm: Let p and q be functions. Then,
>
> > p(x)/q(x) > 0 iff p(x)*q(x) > 0
>
>
>
> Not quite, since when q(x) = 0,
>
> p(x)/q(x) is not defined whereas
>
> whereas p(x)*q(x) is defined and zero, so
>
> "p(x)/q(x) > 0" is indeterminate but
>
> "p(x)*q(x) > 0" is false

A iff B means:

(if A then B) AND (if B then A)

But

If pq < 0 then p/q < 0
If p/q < 0 then pq < 0

Date Subject Author
8/16/13 Kobu
8/17/13 William Elliot
8/17/13 Kobu
8/17/13 Virgil
8/17/13 vrut25@gmail.com
8/21/13 Kobu
8/23/13 vrut25@gmail.com
8/17/13 William Elliot
8/17/13 William Elliot
8/17/13 grei
8/19/13 vrut25@gmail.com
8/21/13 Kobu
8/23/13 tommy1729_