Sine, cosine and tangent are the three most familiar functions in which branch of mathematics?
Trigonometric functions prefix "co-" (in "cosine", "cotangent", "cosecant") is found in Edmund Gunter's "Canon triangulorum" (1620), which defines the "cosinus" as an abbreviation for the "sinus complementi" (sine of the complementary angle) and proceeds to define the "cotangens" similarly. Trigonometric functions In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are functions of an angle. They relate the angles of a triangle to the lengths of its sides. Trigonometric functions are important in the study of triangles and modeling periodic phenomena, among many other applications. The most familiar trigonometric functions are the sine, cosine, and tangent. In
Fourier sine and cosine series defined to be which is just a form of complete Fourier series with the only difference that formula_3 and formula_4 is zero, and the series is defined for half of the interval. In the formula we have ... If f(x) is an even function, then the Fourier cosine series is defined to be where This notion can be generalized to functions which are not even or odd, but then the above formulas will look different. Fourier sine and cosine series In mathematics, particularly the field of calculus and Fourier analysis, the Fourier sine and cosine series are two mathematical series