Geometry: A tangent to a curve at a point P is the straight line through P whose slope is equal to the slope of the curve at P.
Trigonometry: A periodic trigonometric function defined on angles, usually abbreviated “tan.” Can be defined independently or in terms of the trig functions sine and cosine.
See the related article for a complete exposition.
The “trig” functions are transcendental functions defined on angles. They include the sine, cosine, tangent, secant, cosecant, and cotangent functions. See the related article for a complete description.
An established rule for manipulating trigonometric expressions. See the article for a comprehensive listing.
The mathematical subject concerned with trigonometric functions, which are defined on angles. They include the sine, cosine, tangent, secant, cosecant, and cotangent functions.