An interesting mathematical property

AI Thread Summary
The discussion centers on the mathematical property where 3^3 can be expressed as a sum of differences between powers of 3, leading to the equation 27 = [27-9] + [9-3] + [3-1] + 1. This property is identified as a "collapsing sum," which some participants find unclear and seek further explanation on. The concept is compared to a telescoping series, which simplifies the understanding of such sums. Participants express confusion about the relevance of this property to game theory, with no clear connection established. The conversation highlights the mathematical curiosity surrounding the collapsing sum and its representation.
jaquecusto
Messages
12
Reaction score
0
3^3 = [3^3 - 3^2] +[3^2 - 3^1] + [3^1 - 3^0] + 3^0

Practical Demonstration:

27 = [27-9] + [9-3] + [3-1] + 1

27 = 18 +6+2+1

27 = 27

Is this property discussed in theory of games?
 
Mathematics news on Phys.org
I don't understand. What does this have to do with game theory?
 
I'm not sure how this has anything to do with game theory, but what you just found is what's called the collapsing sum.
 
gb7nash said:
I'm not sure how this has anything to do with game theory, but what you just found is what's called the collapsing sum.
What is that, exactly? I'm unclear on what the "interesting property" is. Obviously you can express any number as a sum of differences between a series of smaller numbers. I tried googling "collapsing sum" but found nothing helpful.
 
pmsrw3 said:
What is that, exactly? I'm unclear on what the "interesting property" is. Obviously you can express any number as a sum of differences between a series of smaller numbers. I tried googling "collapsing sum" but found nothing helpful.

I think he means a telescoping series: http://en.wikipedia.org/wiki/Telescoping_series of which the OP gave a (trivial) example.
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Thread 'Video on imaginary numbers and some queries'
Hi, I was watching the following video. I found some points confusing. Could you please help me to understand the gaps? Thanks, in advance! Question 1: Around 4:22, the video says the following. So for those mathematicians, negative numbers didn't exist. You could subtract, that is find the difference between two positive quantities, but you couldn't have a negative answer or negative coefficients. Mathematicians were so averse to negative numbers that there was no single quadratic...
Thread 'Unit Circle Double Angle Derivations'
Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...

Similar threads

Back
Top