trigonometric function

triginometric ratios

A trigonometric function is any of the functions sine (sin), cosine (cos), tangent (tan), secant (sec), cosecant (cosec), or cotangent (cot), or their inverses, sin-1, etc., which deal with certain proportions in right-angled triangles. For example, the sine of an angle θ, sin θ, in a right triangle, is equal to the side opposite the angle divided by the hypotenuse (the longest side). The plane curve generated by a trigonometric function is called a trigonometric curve.