Unit circle is a circle of radius 1(unit) centered at origin(0, 0) in Cartesian coordinate system. A unit circle can be represented as shown in the following figure:
If (x, y) are the coordinates of a point P at circumference of a unit circle, then x and y will be the two sides of right triangle OAP. Using the Pythagorean theorem, the equation of the unit circle is given below:
Here 1 represents the radius of the circle.