A few functions were common historically, but are now seldom used, such as the trigonometric identities.
12.
In this way, this trigonometric identity involving the tangent and the secant follows from the Pythagorean theorem.
13.
In that way, this trigonometric identity involving the cotangent and the cosecant also follows from the Pythagorean theorem.
14.
:Take a look at the first formula under List of trigonometric identities # Angle sum and difference identities.
15.
By applying standard trigonometric identities the two trigonometric functions may be expressed as a single sinusoid with phase shift,
16.
The following may be deduced by applying the principle of superposition to two sinusoidal waves, using trigonometric identities.
17.
Many mathematical theorems can be reduced to more straightforward computation, including polynomial identities, trigonometric identities and hypergeometric identities.
18.
Certain equations involving trigonometric functions are true for all angles and are known as " trigonometric identities ".
19.
The derivations of trigonometric identities rely on a cyclic quadrilateral in which one side is a diameter of the circle.
20.
If they come up, you can just express them in terms of simpler functions as at Trigonometric identities # Definitions.
