MHB Integer ordered pairs in logarithmic equation

Click For Summary
The discussion centers on finding integer ordered pairs (x, y, z) that satisfy a set of logarithmic equations. The constraints indicate that x, y, and z must be less than 6, leading to the transformation of the logarithmic terms into fractions involving square roots. A participant suggests that the only integer solution may be the trivial case where x, y, and z all equal 3, based on the nature of logarithmic functions. The conversation highlights the complexity of the equations and the challenge in determining additional solutions. Ultimately, the focus remains on the potential uniqueness of the solution at (3, 3, 3).
juantheron
Messages
243
Reaction score
1
no. of integer ordered pairs of $(x,y,z)$ in

$ \sqrt{x^2-2x+6}\cdot\log_{3}(6-y) = x $

$ \sqrt{y^2-2y+6}\cdot\log_{3}(6-z) = y $

$ \sqrt{z^2-2z+6}\cdot\log_{3}(6-x) = z $

My approach :: Here $6-x,6-y,6-z>0$. So $x,y,z<6$

Now $\displaystyle \log_{3}(6-y) = \frac{x}{\sqrt{x^2-2x+6}}=\frac{x}{\sqrt{(x-1)^2+5}}$

and $\displaystyle \log_{3}(6-z) = \frac{y}{\sqrt{y^2-2y+6}}=\frac{y}{\sqrt{(y-1)^2+5}}$

and $\displaystyle \log_{3}(6-x) = \frac{z}{\sqrt{z^2-2z+6}}=\frac{z}{\sqrt{(z-1)^2+5}}$

How can I calculate after that.

Help please

Thanks
 
Mathematics news on Phys.org
Re: integer ordered pairs in logarithmic equation

I don't have a reference for this, but I guess that if $n$ is an integer then $\log_3n$ is transcendental unless $n$ is a power of $3$. If so, then the only solution to those equations must be the obvious one $x=y=z=3$.
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

Similar threads

  • · Replies 9 ·
Replies
9
Views
2K
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
11K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
8
Views
2K