For the complex number z=x+iy, where x and y are arbitrary real numbers, y is called the imaginary part of the complex number z, and y = im Z. In Cartesian coordinate system, the value of the y axis is an imaginary number. Using the real part and imaginary part, we can judge whether two complex numbers are equal, define the yoke complex number, and calculate the principal values of the modulus and angle of the complex number.

Complex number classification:

Let the complex number be x+iy, and then define:

Pure imaginary number: a complex number with zero real part is considered to be pure imaginary number, that is, x=0.

Real number: A complex number with an imaginary number of zero is a real number, that is, y=0.

Extended data:

Complex correlation extension: imaginary unit "I"

Source:

The imaginary unit "I" was first invented by the Swiss mathematician Euler, and was not widely used until the German mathematician Gauss advocated it. Gauss first introduced the term "complex number" and recorded it as a+bi. The word "imaginary number" was first put forward by Descartes. As early as 1800, someone used (a, b) to represent a+bi. They may be Curtis, Demovo, Euler and Vandermonde,.

Casbas Veisser, a Norwegian, was the first to express a+bi as a vector, and he was the first to give a vector algorithm for complex numbers. The symbol "I" comes from the French imkginaire-the first letter of "virtual", not from the English imaginarynumber (or imaginaryquautity). The complex set c comes from the first letter of the English word complexnumber.

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