👉 In mathematics, a cotangent is defined as the reciprocal of the tangent function. Specifically, it's used to find the angle of a triangle when one side and its adjacent are known. The cotangent is denoted by $\cot$ or sometimes $\operatorname{cot}$. For example: $\cot(30^\circ) = \frac{\sqrt{3}}{3}$ Note: This definition is only valid for right-angled triangles, where the opposite side and its adjacent