Divergence can be divided into three types: open set, final set and series divergence. Among them, open set refers to a series or function greater than a certain limit value; Terminal set refers to a sequence or function less than or equal to a limited value; Series divergence is especially suitable for finite operations, that is, a series with a finite term is considered to be positive convergence, and if it exceeds this finite term, it is negative convergence. If the final value of this operation does not converge, that is, it is greater than or less than a certain range, it is considered divergent.