All posts by Kyle

To Infinity and Beyond

Hello everyone!

This week, I'd like to talk to you about the infinite.  I'll warn you now, the whole subject is difficult and incredibly counter-intuitive.  Georg Cantor, the guy who first figured most of this stuff out, went crazy, and a lot of his contemporaries found his ideas too radical to believe.  So don't worry if you don't get it right away.  This one's hard.

To get our first taste of infinity, let's begin with Galileo's paradox (yes, that Galileo).  Line up the whole numbers () next to their squares, as shown below.  Now, we've paired each one of the whole numbers with one of the square numbers, so it might be reasonable to say that there are exactly as many whole numbers as square numbers.  But hold on a second - all of the square numbers are already whole numbers, and lots of whole numbers (like ) aren't square, so there should be less squares than whole numbers!  What's going on here?galileo Continue reading To Infinity and Beyond

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Induction

Hello everyone!

Induction is one of the most useful proof techniques available.  The basic idea is fairly simple: one case works because the previous case worked.  That's sort of abstract, so let's dive into an example.

There's a famous story (in the mathematical world) about an 7-year-old Gauss calculating in a few seconds.  Let's generalize this a bit to show that .  There are a lot of ways to see this, but this week's theme is induction, so let's try that. Continue reading Induction

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Fibonacci Tilings

Hello, everyone!

As I mentioned in my opening post, one of my interests is combinatorics.  Basically, it amounts to counting things cleverly.  It's probably not the most practical field (although it has its uses in statistics and quantum physics), but I find that it has some of the most beautiful and intuitive results.

One of the most studied topics in combinatorics is the Fibonacci sequence.  We start with then we get each other term by adding the previous two.  So the first few terms are .  More algebraically, we have and   Those are nice numbers, I guess, but what do they mean? Continue reading Fibonacci Tilings

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Happy Pi Day!

Hello, everyone, and Happy Pi Day!

You've almost assuredly seen the number before.  It shows up in all sorts of odd places.  So what is ?  You probably know but that might feel like I'm pulling a number out of the air.  Where does it really come from?

First, let's start with the definition: is the ratio of a circle's circumference to its diameter.  That is, if you took the circle and unrolled it (as below), the line segment you end up with is times the width of the circle at its widest point.

unrollCircle Continue reading Happy Pi Day!

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Hello World!

Hello, everyone!

Before I launch into the content, I should probably introduce myself.  I'm Kyle.  I'm currently a college senior studying math and computer science.  In particular, I like areas such as combinatorics (fancy counting), graph theory (the study of networks), and algorithms (getting useful information out of lots of data), but my mathematical interests are pretty broad.  I'm also a huge fan of puzzles, in pretty much every form.  Jigsaws, crosswords, sudoku, chess, etc.  I like things that make me stop and think.

So why am I making this blog?  I've heard a lot of people say they hate math.  The thing is, what they think of as "math" is calculation.  It's taking a few numbers, following a set of rules, and arriving at another number.  I suppose that could be considered useful, but it's computation, not math.  We've invented computers to do that for us.  Math is something else entirely.  It's useful, it's logical, and, if you ask me, it's beautiful.  It's a way of systematically reasoning about the world.  It's about proving that assumptions lead to conclusions without any room for doubt.

That's a pretty vague statement, so let me clarify with an example.

You may have heard that the whole numbers (1, 2, ) go on forever.  But how do we know that?  Well, let's say they don't.  Then there has to be a largest whole number.  It has to be pretty big, as it's larger than every other number you can think of, so let's call it   What happens if we add one to it?  We really don't know much about but we do know that adding one to any number makes it bigger, so   But that can't be right; we've got a whole number bigger than when we assumed that was the largest.  That means one of our assumptions must have been wrong.  The only assumption we made along the way was that there is a biggest whole number, so that must not be true.  Thus, the whole numbers must go on forever.

This is a pretty simple example, but we can derive much more interesting results in a lot of fun ways.  I hope you'll follow along to see some of the power and beauty of mathematics.

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