From Citizendium, the Citizens' Compendium
- Image:Circle-trig6.svg|300px|right|thumb|All of the trigonometric functions of an angle θ can be constructed geometrically in terms of a unit circle centered at O.
- Image:Trigonometry triangle.svg|right|thumb|A right triangle always includes a 90° (π/2 radians) angle, here labeled C. Angles A and B may vary. Trigonometric functions specify the relationships between side lengths and interior angles of a right triangle.
- Image:Unit_circle_angles.svg|300px|thumb|right|The unit circle
- Image:Sine cosine plot.svg|300px|right|thumb|The f(x) = sin(x) and f(x) = cos(x) functions graphed on the cartesian plane.
- Image:Sine ani.gif|right|400px|thumb|A sin(x) animation which shows the connection between circle and sine.
- Image:Tangent.svg|300px|right|thumb|The f(x) = tan(x) function graphed on the cartesian plane.
- Image:Circle-trig6.svg|300px|right|thumb|All of the trigonometric functions can be constructed geometrically in terms of a unit circle centered at O.
- Image:Taylorsine.svg|300px|thumb|right|The sine function (blue) is closely approximated by its Taylor polynomial of degree 7 (pink) for a full cycle centered on the origin.
- Image:Synthesis_square.gif|thumb|350px|right|Animation of the additive synthesis of a square wave with an increasing number of harmonics
- Image:LissajousCurve5by4.PNG|right|thumb|right|A Lissajous curve, a figure formed with a trigonometry-based function.