double angle formula

double angle formula

[¦dəb·əl ′aŋ·gəl ‚fȯr·myə·lə]

(mathematics)

An equation that expresses a trigonometric function of twice an angle in terms of trigonometric functions of the angle.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.