Greek Alphabet in Math

Mathematics and science the formulas frequently make use of letters from the Greek alphabet instead of the boring old a, b, c and x, y, z variables we are used to seeing in simple Algebra.

In math and science, the capital and small Greek letters are usually used for different things.  Here are a few examples, not the whole Greek alphabet, showing some of the ways the Greek letters are used:

Letter Usage
The most frequently used Greek letter is a small letter pi (pronounced pie) used to represent the ratio of the circumference of a circle to its diameter. Pi is an irrational number meaning it is a decimal that never repeats. With scientific calculators, look for the pi button to get a very good, but not exact answer. If you don't have a scientific calculator, you can estimate pi as 22/7 or 3.14159.
α alpha,
β beta, and θ theta
In Trigonometry, Greek letters are used to represent angles. While any small Greek or regular letter can be used, the most popular are the small letters alpha, beta, and theta.
Delta is used to represent changes. Large Δ delta can be used to show relatively large changes.
One example is the slope equation: change in y divided by change in x is written Δy/Δx
Small delta δ is used in Calculus to represent very tiny changes, for example instantaneous slope is δy/δx
Small sigma σ is used to represent the standard deviation in statistical calculations. 
Large sigma Σ is used for summation, when you are adding up things with repeated use of a formula and a changing variable.
Small lambda is used by physicists to represent wavelength, usually of light

Be sure to visit the Math Academy article about the Greek alphabet to find out more about the Greek letters and how they are used.

Comments, questions, or you just need some help? Send an e-mail to Mrs. Shearer Last Updated: 02/04/2011
K. A. Shearer 2006
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