Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Double and Half Angle Formulas
Twenty-two problems present a variety of practice working with double-angle and half-angle formulas. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the...
Wolfram Research
Wolfram Math World: Hyperbolic Functions
This site from MathWorld explains the hyperbolic function. The information is not too in-depth, but factual and quite a few links are provided for additional information on related subjects.
Wolfram Research
Wolfram Math World: Double Angle Formulas
Part of Eric Weisstein's comprehensive math site, this page deals with double-angle formulas. This site includes traditional trigonomic double-angle functions as well as hyperbolic trigonometric function. Includes links to related terms...
Math Medics
S.o.s. Math: Double Angle and Half Angle Formulas
Double angles and half angles are explained through step by step examples. The steps are clear and easy to follow.
Math Medics
S.o.s. Math: Trigonometry
This lesson is the main SOS Math page for trigonometry. Surf the lesson to find most any trigonometric identity, formula, and many forms of help in the area of trigonometry.
Free Math Help
Free Math Help: Double and Half Angle Formulas
Students learn about the double and half angle formulas. Definitions and formulas are included.
eFunda
E Funda: Multiple Angle
At this site from eFunda you can scroll to the middle of the page for a listing of multiple angle formulas for cos, sin, and tan.