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#1 2008-03-03 22:51:58

gyanshrestha
Member
Registered: 2007-11-06
Posts: 41

solve

solve for x


autually the power is 2/3 and 1/3.
soryy for inconvinieces

Last edited by gyanshrestha (2008-03-03 23:00:51)


http://gyan.talkacademy.com.np

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#2 2008-03-04 01:00:34

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

Re: solve

Your equation is

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#3 2008-03-04 02:08:25

gyanshrestha
Member
Registered: 2007-11-06
Posts: 41

Re: solve

yes and thanks  JaneFairFax
actually i am confusing on giving the exponets.
can any one solve? please.


http://gyan.talkacademy.com.np

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#4 2008-03-04 02:08:26

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: solve

From this we know

and
must both be rational numbers, since the sum of two irrational numbers is irrational.

So the cube root of two rational numbers add to 3.

Listing them out, we find that

, for instance, seems a likely candidate. But
, so it cannot be solved.

I haven't proven this because I'm sleepy but I think that there exists no number such that the sum of it's cube root and its reciprocal's cube root can give 3.

i.e. no solution (not QED)

Last edited by Identity (2008-03-04 02:09:19)

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#5 2008-03-04 02:11:02

gyanshrestha
Member
Registered: 2007-11-06
Posts: 41

Re: solve

then can we solve the equation in terms of a?


http://gyan.talkacademy.com.np

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#6 2008-03-04 02:19:19

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: solve

Of course! I didn't notice that two irrational numbers could be added like that... in class my teacher actually told us that two irrational numbers summed to another irrational number. roflol

Last edited by Identity (2008-03-04 02:21:04)

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#7 2008-03-04 02:19:42

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

Re: solve

Identity wrote:

since the sum of two irrational numbers is irrational.

The way to solve the equation is to let

so you have

PS: Sorry, Identity. I deleted my previous post and reposted this one – but you replied in the meantime. tongue

Last edited by JaneFairfax (2008-03-04 02:22:30)

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#8 2008-03-04 02:22:31

gyanshrestha
Member
Registered: 2007-11-06
Posts: 41

Re: solve

actually the equation was given by a student of my friend and has aslo has solution that is 2a/sqrt5.
how does it come?


http://gyan.talkacademy.com.np

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#9 2008-03-10 22:52:28

shree
Guest

Re: solve

i posted its answer two or three days ago and it was successfully posted but now its gone.
how could this be

#10 2008-03-11 03:28:52

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

Re: solve

That's probably because you posted while the servers were being switched. We unavoidably lost about a day's posts around then.
There was an announcement that that would happen though.


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

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