Now that the MMM #35 deadline has passed …

June 30th, 2009

MMM #35 turned out to be harder than I thought judging by the small number of submissions I received.

I’ll be giving away four prizes on Friday - two to the early submitters, one to .mau. for consistently submitting entries to the contest for a really long time, and one to a randomly selected person with a correct submission.

I’ll discuss some of the solutions on Friday but, for now, check out these pictures I made. I came up with this problem by playing with the Fibonacci series and arranging rectangles.

Here is the problem description:

Let F(0)=1, F(1)=1, and F(n)=F(n-2)+F(n-1). This is the familiar Fibonacci series.

Simplify F(0)xF(1) + F(1)xF(2) + F(2)xF(3) + F(3)xF(4) + … + F(n-1)xF(n) + F(n)xF(n+1)

Show your work.

Can you see how these pictures help one to see why the sum is what it is? Do you see why there are two different pictures?



If you enjoyed this post, make sure you subscribe to my RSS feed!

Can you sum this?

June 29th, 2009

Hi,

I’ve been playing with this series:

Sn = 1×22 + 2×32 + 3×42 + … + nx(n+1)2

I’ve come up with a formula for determining Sn but I derived the formula in a fairly roundabout way.

I’m interested to know if someone has an elegant way to derive the formula.

If you enjoyed this post, make sure you subscribe to my RSS feed!

MMM #35: Is it too hard?

June 25th, 2009

I’ve only gotten two solutions to the “Fibonacci Fun” problem I proposed. Is everyone on vacation and not thinking about Math, do people find the problem boring or is it too hard? I don’t think it’s one of my harder problems. I want to state that I approached the problem in a different way than each of the people who provided solutions. So, there are at least three ways to approach the problem.

If you don’t know how to approach it I suggest looking for a pattern in the sum as you add more terms.

Come on, give it a try! You could win $10.

This time around, since I’ve given you guys a hint, I’ll give three prizes - one each to the two people who have solved it already and one to a randomly other person with a correct solution.

If you enjoyed this post, make sure you subscribe to my RSS feed!