Group of rational points on the unit circle

The group of rational points on the unit circle refers to the set of points \( (x, y) \) on the unit circle defined by the equation \[ x^2 + y^2 = 1 \] where both \( x \) and \( y \) are rational numbers (numbers that can be expressed as fractions of integers). To describe the rational points on the unit circle, we can parameterize the unit circle using trigonometric functions or with rational parameterization.