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#1 2013-11-20 20:11:04

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,028

polynomial

If    x +1/x=m ,   x² +1/x³ =n,

Then  what will be the value of   x³ +1/x² .

I tried and got the value ‘nx’, but am not able to convert x in terms of m and n.

Pls help.


friendship is tan 90°.

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#2 2013-11-20 22:10:41

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,531

Re: polynomial

hi niharika_kumar

This looks like you need to use

and

Can you finish it from there?

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#3 2013-11-21 00:26:03

Bezoux
Member
Registered: 2013-11-17
Posts: 7

Re: polynomial

Here's my, in my opinion, a fairly elegant solution smile .
There might be a silly arithmetic mistake in there, but I think that was the idea.








Last edited by Bezoux (2013-11-21 00:32:30)

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#4 2013-11-21 02:38:25

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,028

Re: polynomial

its not that simple.
i tried but failed that way.
then i multiplied the 2 equations,substituted some of the values and got the result as nx.
now i just need to convert nx in terms of m and n only but am always ending up my result in the variable x.
pls. help.


friendship is tan 90°.

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#5 2013-11-21 03:05:47

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,531

Re: polynomial

hi niharika_kumar

Bezoux and I have shown you a method that works.  I agree with Bezoux's answer.

We don't know how to deal with nx because we don't have that.

If you want to stick with your method, you will have to post it here.  Then we can check it and either tell you where the mistake is, or show you what else is needed.  smile

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#6 2013-11-21 16:43:54

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,028

Re: polynomial

yes i got it.
The answer printed after the ques. was wrong. Bezoux's answer is completely correct.
thanks for your help bezoux and bob. smile


friendship is tan 90°.

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