In a plane, a closed curve formed by a moving point rotating around a certain point with a certain length is called a circle. A circle has countless axes of symmetry. On the same plane, the set of points whose distance to a fixed point is equal to a fixed length is called a circle.
A circle can be expressed as a set {m |||| mo | = r}, where o is the center of the circle and r is the radius. The standard equation of a circle is (x-a)+(y-b)=r, where point (a, b) is the center of the circle and r is the radius.
The Mathematical Meaning of C Language
In elementary school mathematics, it represents the circumference of a circle. In high school mathematics, c is a complex set and a constant. C is marked with a number, the subscript a number is a combination number, CuA is the complement of subset A in the complete set U, and the Greek letter π here represents the ratio of circumference to diameter as usual, which is π.
Modern mathematicians can use calculus or more advanced subsequent theoretical analysis to get this area. But Archimedes, a great mathematician in ancient Greece, proved by Euclidean geometry that the area in a circle is equal to the area of a right triangle with perimeter and radius as two right-angled sides.