I is an imaginary unit in mathematics, representing a theoretical quantity in mathematics. I stands for a point on a plane in a mathematical system. This point is away from the origin 1 and counterclockwise from the x axis 1/4 unit circles. I is used to solve some mathematical problems, including complex numbers, specific functions and constants, trigonometric functions, calculus and differential equations.

I is the imaginary unit in the complex number, that is, I 2 =-1. Imaginary numbers are used to describe mathematical and physical phenomena or results that cannot be expressed by normal real numbers, such as voltage and current in circuits, vibration and fluctuation in physics, square root of negative numbers in mathematics, ordinary differential equations and so on. Imaginary number is a concept in theory, but it is also widely used in practical application.

I is a very basic mathematical concept, which has important applications in many branches of mathematics, such as complex analysis, trigonometric function, calculus, equations and so on. The introduction of I not only expands the range of solvable problems in mathematics, but also has been widely used in practical applications, especially in electronic engineering, physics and cybernetics. I is an abstract mathematical concept, which is different from real numbers in this respect, but its application and importance are irreplaceable in modern science and technology.