👉 In mathematics, a cotwin is a pair of numbers that are related by an identity such as sine and cosine. They are often used in trigonometry to describe angles that are complementary or supplementary to each other. The term "cotwin" comes from Latin and means "cousin," referring to the fact that it is a pair of numbers that share a common unit of measure, usually the length of a side of a right triangle. In this context, the angle formed by these two