Purpose of Algebra
Date: 10/15/96 at 8:23:59 From: Landon Stuckey Subject: Purpose of Algebra What is the purpose of algebra and who came up with the idea of algebra? Sincerely, Landon Stuckey
Date: 10/16/96 at 14:0:42 From: Doctor Ceeks Subject: Re: Purpose of Algebra Hi, Your second question is much easier to answer, so I'll start with that one. The idea of algebra has occurred to many in the past, and it is unclear who was the very first to come up with the idea. Okay, now to your first question. Algebra is useful for many things. It's like this. You're studying some objects and how they behave and interact. You notice some patterns that happen over and over. You try to eliminate all the unnecessary details and grasp the essence of what is going on. You find out that you can describe what is going on by explaining some rules. You discover that these rules describe many, many things and imply some things you never thought of before. You end up explaining lots of new things. You have then created an algebra and used it with purpose. (Technically, the word "algebra" is now used by mathematicians to mean a very special kind of thing, but that won't matter unless you go to graduate school in mathematics.) Here's an example of the above. You're playing with a square. You notice that you can move the square some ways without making it seem like you moved the square. For instance, you can flip it around one of its diagonals. Or, you can rotate it 90 degrees clockwise (or counter-clockwise). You notice that sometimes, you can follow such a motion by another such motion and get something new which doesn't affect the square. You want to understand these motions. You decide to simplify things by simply denoting the rotation by 90 degrees clockwise by R and the 90 degree counter-clockwise rotation by L. You decide to write RR for the motion you get when you do R twice. You find that RRRR is really the same as doing absolutely nothing. You notice that RRR is the same as L, and LLL=R. You find that RR=LL. You find that you can't get the flip about the diagonal using just R and L, so you call it F. You keep exploring, and "algebra" just naturally pours forth! Eventually you may discover everything you can do to a square. You may see that with just R and F, you can get everything! You may try to do this for a regular pentagon, then a regular hexagon...even, a regular n-gon! Are they really so different? If you have fun doing this, and you do it a lot, welcome to the world of algebra... you're an algebraist. Usually, people first encounter algebra when they study the algebra of numbers. So you may be more used to seeing things like 3x+5=y, where x and y stand for numbers. The algebraic rules numbers obey are commutativity: x+y = y+x, associativity: (x+y)+z = x+(y+z), and distributivity: x(y+z) = xy+xz. There's also a special number, called zero, and denoted 0. It has the property that x+0=x.) -Doctor Ceeks, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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