A university matrix is very similar to a vector, except that the vector is linear and the matrix is flat. Matrices have their own operations, and the point multiplication of vectors can be represented by the multiplication of two matrices. It is very convenient to solve the series problem with matrix, but first we must know the operation rules of matrix. I'm ashamed to say that I learned The Matrix two years ago, and now I almost forget it. Of course, not all problems can be explained by matrices. I think it is most appropriate to use the high school method to do high school problems, and there is no need to learn college things.