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Topic: Help Needed in math
Replies: 25   Last Post: May 2, 2014 6:01 PM

 Messages: [ Previous | Next ]
 Peter Percival Posts: 2,623 Registered: 10/25/10
Re: Help Needed in math
Posted: Apr 29, 2014 8:03 AM

William Elliot wrote:
> On Mon, 28 Apr 2014, Peter Percival wrote:
>> punisher wrote:
>>

>>> Find the largest values of the integer a for which ax^2-5x-3 is
>>> negative for all values of x.

>
>> Minus three.
>
> ax^2 - 5x - 3
> (5 +- sqr(25 + 12a)/2a
> 25 + 12a < 0; a < -25/12

At this point one concludes that -3 is the answer.

> ax^2 - 5x - 3 < -25x^2 / 12 - 5x - 3 < 0 ?
> -25x^2 - 60x - 36 = -(5x + 6)^2 <= 0
>

--
...if someone seduced my daughter it would be damaging and horrifying
but not fatal. She would recover, marry and have lots of children...
On the other hand, if some elderly, or not so elderly, schoolmaster
seduced one of my sons and taught him to be a homosexual, he would ruin
him for life. That is the fundamental distinction. -- Lord Longford

Date Subject Author
4/28/14 punisher
4/28/14 quasi
4/29/14 Peter Percival
4/29/14 Karl-Olav Nyberg
4/28/14 Peter Percival
4/29/14 William Elliot
4/29/14 Peter Percival
4/29/14 Karl-Olav Nyberg
4/29/14 Karl-Olav Nyberg
4/29/14 Karl-Olav Nyberg
4/29/14 Karl-Olav Nyberg
4/29/14 William Elliot
4/30/14 Karl-Olav Nyberg
4/30/14 William Elliot
4/30/14 Karl-Olav Nyberg
4/30/14 William Elliot
5/1/14 Karl-Olav Nyberg
5/1/14 William Elliot
5/1/14 quasi
5/2/14 William Elliot
5/2/14 quasi
5/2/14 William Elliot
5/2/14 snmpprotocol@gmail.com
5/2/14 quasi
5/2/14 Karl-Olav Nyberg
5/2/14 quasi