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 |

π pi |
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. |

Δ δ delta |
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 |

Σ σ sigma |
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. |

λ lambda |
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.

© K. A. Shearer 2006

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