Tangent (trigonometry)

In trigonometry, the tangent of an angle in a right triangle is the ratio of the length of the side opposite the angle to the length of the side adjacent to it. It can equally be defined as the ratio of the sine of the angle to its cosine, and it is the reciprocal of the cotangent function. On the unit circle, the tangent of an angle corresponds to the y coordinate of the point where the ray at that angle meets the vertical line at x equal to one. Unlike sine and cosine, which repeat every full turn, the tangent function has a fundamental period of only half a turn, so that its value at an angle equals its value at that angle plus any integer multiple of that half turn period. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/