Weird pattern in exponentiation

  • Thread starter Thread starter StatusX
  • Start date Start date
  • Tags Tags
    Weird
StatusX
Homework Helper
Messages
2,570
Reaction score
2
I was looking at the different ways the operations +, *, and exponentiation can work on three numbers x, y, and z. I found a weird pattern when the second operation performed is exponentiation. These are the expressions:

(x+y)^z \ x^{(y+z)} \ (x \cdot y)^z \ x^{(y \cdot z)} \ (x^y)^z \ x^{(y^z)}

Notice how I arranged them in a natural way, where the first operation(inside the parantheses) is (+,+,*,*,^,^), and the second operation, exponentiation, is carried out on the (R,L,R,L,R,L) of the parantheses. Now look at the pattern:

(x+y)^z \ \ \ \ \ \ \ \ \ x^{(y+z)} \ \ \ \ \ \ \ \ \ (x \cdot y)^z \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x^{(y \cdot z)} \ \ \ \ \ \ \ \ \ (x^y)^z \ \ \ \ \ \ \ \ \ x^{(y^z)}

largest ...<- identical ->... | ...<- indentical ->... largest

written ... written ... | ... value ..... value
formula ... formula

I'm sorry if this doesn't format right, but I'll explain what it means. (x+y)^z has the largest identity expression, in terms of the size of the written formula: the binomial theorem. x^{(y+z)} and (x \cdot y)^z are equal to x^y \cdot x^z and x^z \cdot y^z respectively, so the shape of their written formulas are identical. x^{(y \cdot z)} is equal in value to (x^y)^z. And finally, x^{(y^z)} has the largest value, for x,y,z>>1.

This seems like a very bizarre link between the "man-made" (sort of) written formulas and the "completely natural" values of these expressions. Is there anything to this, or is it just a coincidence?
 
Mathematics news on Phys.org
I have no idea why you consider your arrangement to be "in a natural way". There would be absolutely no difference that I can see if you were to arrange them in any other way.
 
They are arranged regularly. You might argue if its natural or not, although I'm pretty sure they are in order of increasing value for x,y,z >>1, which seems pretty natural.
 
So does this need to be explained, or am I reading too much into it? I could see how you might argue the arrangement is arbitrary, but its at least in increasing order of the "power" of the first operation, ie., (+,+),(*,*),(^,^). Then the only choice I made that may seem arbitrary is which side the exponent should be on in the first of each pair, and I picked the right side. But like I said, I also think they are in order of value for numbers >>1 (maybe just >2?), but I'm not completely sure about that.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
Back
Top