Ask the great god of mathematics to tell me something about y 2 =-1.

Negative numbers are imaginary numbers. Definition: I is an imaginary symbol, and the root is also positive and negative. From y 2 =-1, y= plus or minus i. In a rectangular coordinate system, the abscissa corresponds to the real part, and the ordinate corresponds to the imaginary part. The coordinate system where the complex number is located is a complex plane, such as the 0+I question and the 0-I question, which are at (0, 1) and (0,1) points respectively.