Толковый словарь английского языка - cotangent

noun Etymology: New Latin ~-, cotangens, from co+ tangent-, tangens tangent Date: 1635 a trigonometric function that for an acute angle is the ratio between the leg adjacent to the angle when it is considered part of a right triangle and the leg opposite, a trigonometric function cot θ that is equal to the cosine divided by the sine for all real numbers θ for which the sine is not equal to zero and is exactly equal to the ~ of an angle of measure θ in radians