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#1 2014-03-15 06:19:19

PatternMan
Member
Registered: 2014-03-08
Posts: 147

Can anyone prove this = or non equal?

n
------
x - y   

= or not = 

n+y
------
   x

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#2 2014-03-15 06:22:25

ShivamS
Member
Registered: 2011-02-07
Posts: 3,415

Re: Can anyone prove this = or non equal?

By ----- do you mean divide?

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#3 2014-03-15 06:24:10

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,124

Re: Can anyone prove this = or non equal?

hi

You only need one counter example to prove it is false.  Try choosing some numbers for n, x and y.

Bob


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

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#4 2014-03-15 06:24:15

ShivamS
Member
Registered: 2011-02-07
Posts: 3,415

Re: Can anyone prove this = or non equal?

If you do, it's false. Counterexample: n, x is 2, y is 1
2/(2-1) doesn't equal (2+1)/2

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#5 2014-03-15 06:42:48

PatternMan
Member
Registered: 2014-03-08
Posts: 147

Re: Can anyone prove this = or non equal?

ShivamS wrote:

If you do, it's false. Counterexample: n, x is 2, y is 1
2/(2-1) doesn't equal (2+1)/2

This is proof by what? So you only need one instance of a counterexample to prove it's false but you need to use variables to prove something is true. Well I found I found some numbers that made it true and I was going to use it to solve a problem but realized that it might not be true for all numbers and turns out it isn't.

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#6 2014-03-15 06:44:49

ShivamS
Member
Registered: 2011-02-07
Posts: 3,415

Re: Can anyone prove this = or non equal?

To prove it false, you need only one counterexample. To prove it true, there are several methods like contradiction, induction. A great book on proofs is How to Prove It: A Structured Approach by Daniel J. Velleman.

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