Diophantine Equations (Problem \(9\))

xy+yz+zx1=k2x^y + y^z + z^{x - 1} = k - 2

Find solutions where x,y,z,kx, y, z, k are all positive or negative integers.

Give your answer as the number of solutions.

You're solving for kk.

#Algebra

Note by A Former Brilliant Member
11 months, 3 weeks ago

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Comments

@Yajat Shamji- For positive integers x,y,z,kx,y,z,k there are infinite solutions:

Take random positive integers x,y,zx,y,z then xyZ+;yzZ+;zx1Z+(xy+yz+zx1)Z+x^y\in Z^+; y^z\in Z^+; z^{x-1}\in Z^+\Rightarrow (x^y+y^z+z^{x-1})\in Z^+ (k2)Z+\Rightarrow (k-2)\in Z^+ As 2Z+2\in Z^+ kZ+;k>2\Rightarrow k\in Z^+;k>2

Zakir Husain - 11 months, 3 weeks ago

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So you're saying I have made a Diophantine equation that has infinite integer solutions? @Zakir Husain

A Former Brilliant Member - 11 months, 3 weeks ago

What about k2k \leq 2? @Zakir Husain

A Former Brilliant Member - 11 months, 3 weeks ago

What I usually do is code these equations. In my output, I got the fact that if you put x=1,y=1,k=5,x=1,y=1,k=5, there are infinite values for zz. Also, I haven't studied these in school, so I am not at all comfortable in solving using algebra. But there are infinite solutions.

Vinayak Srivastava - 11 months, 3 weeks ago

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You're solving for kk, actually, @Vinayak Srivastava

A Former Brilliant Member - 11 months, 3 weeks ago

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But it's not stated. Then we need solutions of the form (x,y,z,k)(x,y,z,k).

Vinayak Srivastava - 11 months, 3 weeks ago

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@Vinayak Srivastava Ok. I'll add that.

A Former Brilliant Member - 11 months, 3 weeks ago

@Vinayak Srivastava Added.

A Former Brilliant Member - 11 months, 3 weeks ago

@Zakir Husain

A Former Brilliant Member - 11 months, 3 weeks ago

@Chris Sapiano

A Former Brilliant Member - 11 months, 3 weeks ago

@Sahar Bano

A Former Brilliant Member - 11 months, 3 weeks ago

@Hamza Anushath

A Former Brilliant Member - 11 months, 3 weeks ago

@Gandoff Tan

A Former Brilliant Member - 11 months, 3 weeks ago

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Sorry, but Algebra is my mortal enemy, I'm very bad at it.

A Former Brilliant Member - 11 months, 3 weeks ago

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It is not an algebra but a number theory problem. It is from a branch of number theory called Algebraic number theory

Zakir Husain - 11 months, 3 weeks ago

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@Zakir Husain 'Algebraic' Number theory, how's it different?

A Former Brilliant Member - 11 months, 3 weeks ago

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@A Former Brilliant Member There are two broad branches of number theory- Analytic number theory and Algebraic number theory. The difference is that Algebraic number theory uses algebra as a way to get answers to number theory problems like this one. In algebra you will not discriminate between integer, rational, real or complex solutions to the equation but for number theory it matters.

Zakir Husain - 11 months, 3 weeks ago

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@Zakir Husain See algebra is used, so I'm out.

A Former Brilliant Member - 11 months, 3 weeks ago
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