How many positive integral solutions $(x,\,y)$ are there for the equation $\dfrac{1}{x+1}+\dfrac{1}{y}+\dfrac{1}{y(x+1)}=\dfrac{1}{2015}$?

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In summary, to solve the equation with positive integral solutions, you can multiply both sides by 2015 and use algebraic techniques to simplify it. The number 2015 is significant as it represents the sum on the right side and makes the equation more challenging. There are restrictions on x and y, as they cannot be zero and must be positive integers. There are multiple positive integral solutions, but no non-integer solutions are possible.
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anemone
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Here is this week's POTW:

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How many positive integral solutions $(x,\,y)$ are there for the equation $\dfrac{1}{x+1}+\dfrac{1}{y}+\dfrac{1}{y(x+1)}=\dfrac{1}{2015}$?

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No one answered to this POTW. (Sadface) However, you can find the suggested solution below:
$\dfrac{1}{x+1}+\dfrac{1}{y}+\dfrac{1}{y(x+1)}=\dfrac{1}{2015}$ simplifies to $xy-2015x-2014y=2(2015)$ and therefore $(x-2014)(y-2015)-2014(2015)=2(2015)$. Make $(x-2014)(y-2015)$ as the subject and factorize the other side as simplest as possible we have $(x-2014)(y-2015)=2^5\cdot 3^2 \cdot 5 \cdot 7 \cdot 13 \cdot 31$.

Hence, the number of factors of this number is $(5+1)(2+1)(1+1)(1+1)(1+1)(1+1)=288$.
 

FAQ: How many positive integral solutions $(x,\,y)$ are there for the equation $\dfrac{1}{x+1}+\dfrac{1}{y}+\dfrac{1}{y(x+1)}=\dfrac{1}{2015}$?

What is the general approach to solving this equation?

The general approach to solving this equation involves manipulating the equation algebraically to isolate the variables and then using number theory techniques to find the solutions.

Are there any specific restrictions on the values of x and y?

Yes, since the equation involves fractions, x and y must be positive integers. Additionally, x cannot be equal to -1 or 0, as this would result in undefined values.

How many solutions are possible for this equation?

There are infinitely many solutions for this equation. However, we can use number theory techniques to find the specific values of x and y that satisfy the equation.

Can this equation be solved using a computer program?

Yes, this equation can be solved using a computer program. However, due to the infinite number of solutions, the program would need to be designed to find all possible solutions.

Are there any real-world applications of this equation?

Yes, this equation has applications in fields such as cryptography, where finding solutions to equations involving fractions is important for creating secure codes and algorithms. It also has applications in number theory and algebraic geometry.

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