Complex number refers to a number composed of real number and imaginary number. Complex numbers are expressed in the form of a+bi, where A is the real part, B is the imaginary part and I is the imaginary part.

Complex number is the most basic object and tool in complex variable function theory, analytic number theory, Fourier analysis, fractal, fluid mechanics, relativity, quantum mechanics and other disciplines.

Knowledge expansion

Complex number is a unique mathematical concept, which expands the scope of real numbers and becomes an important branch of mathematics. Complex number consists of real number part and imaginary number part. The introduction of imaginary number part is the biggest difference between complex number and real number.

The form of complex number is usually expressed as a+bi, where A is the real part, B is the imaginary part and I is the imaginary part. This form can not only represent real numbers, but also imaginary numbers. The appearance of imaginary numbers makes the range of complex numbers wider. For example, we have a number x, which can be expressed as x=a+bi, where a and b are real numbers and I is imaginary unit.

The appearance of complex numbers has a far-reaching impact on the development of mathematics. It not only plays an important role in solving some practical problems, but also brings many new ideas and theories to the field of mathematics.

For example, when solving some physical problems, such as electromagnetism and fluid mechanics, complex numbers are widely used. In addition, complex function theory, analytic number theory, Fourier analysis and other disciplines are also inseparable from the application of complex numbers.

The application of complex numbers is not limited to the field of mathematics. Complex numbers also play an important role in economics, biology, computer science and other fields. For example, in economics, complex numbers are used to calculate financial problems such as interest and discount;

In biology, plural numbers are used to describe life activities such as cell growth and reproduction. In computer science, complex numbers are used in signal processing, image processing and other fields.

In a word, complex number is a very important mathematical concept, which not only expands the scope of real numbers, but also brings new ideas and theories to the development of mathematics and other disciplines. By studying complex numbers, we can better understand some problems in mathematics and physics, and we can also apply mathematical knowledge to other fields.

Therefore, we should seriously study and master the knowledge of complex numbers in order to better apply it to solve practical problems and problems in other disciplines.