Trigonometric identities are identities in mathematics that involve trigonometric functions such as sin(x), cos(x) and tan(x). Identities, as opposed to equations, are statements where the left hand side is equivalent to the right hand side. A symbol, which means ‘equivalent’, is used instead of the which means ‘equals’. Equations can be solved to find values of x for instance. An identity, however, cannot be solved, no additional information has been given but they can be used to solve equations. See Trigonometric Equations.
AS-Level Trigonometric Identities
These are the formulae that you should memorise for the first year of your A-Level in Mathematics:
These identities can be seen by performing trigonometric graph transformations.
A-Level Trigonometric Identities
These are the formulae that you should memorise for the second year of your A-Level in Mathematics:
Double Angle Formulae
Compound Angle Formulae
For more trigonometric identities visit Wikipedia Trig. Identities.
See other Things to Remember.