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Topic: ---- --- --- --- validity of an equation
Replies: 5   Last Post: Mar 14, 2013 6:20 PM

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quasi

Posts: 10,208
Registered: 7/15/05
Re: ---- --- --- --- validity of an equation
Posted: Mar 2, 2013 3:08 PM
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You removed the relevant context, so I'll remove still
more.

In the reply you snipped, I showed:

If x,y,z are integers such that

y^(1/2) = (x^10 - z^5)^(1/5)

then, letting w = x^10 - z^5, the equation reduces to

y^5 = w^2

which implies y is a perfect square and w is a perfect 5'th
power.

Now you ask, what if we assume that y is not a perfect square?

Then you get a contradiction, of course.

A triviality.

quasi



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