Date: 04/14/97 at 10:22:18 From: Cecil Allen Subject: Theta What is Theta? Does it have a constant value?
Date: 04/14/97 at 12:39:44 From: Doctor Wilkinson Subject: Re: Theta The Greek letter theta is just used as a variable name, much like x and y. For some reason it is most commonly used to denote an angle. But no, it doesn't have a constant value. The most common use is as the angle coordinate in polar coordinates. That is, the point designated by (x, y) in so-called Cartesian coordinates (so-called after Rene Descartes, who invented them), is usually denoted by (r, theta) in polar coordinates. That is, (r, theta) denotes the point whose distance from the origin is r and such that the angle between the positive x-axis and a ray drawn from the origin through the point is theta. The Cartesian and polar coordinates are related by the formuulas x = r cos(theta) y = r sin(theta). In very advanced mathematics there are things called theta functions, but I think that's probably not what you were looking for. I have tried to cover as many uses of theta as I could think of. I hope I have succeeded in answering your question. -Doctor Wilkinson, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.