Theorem 1 ( bounded sum test ) a series of nonnegative terms converges if and only if it ' s partial sums are bounded above 定理1正项级数收敛的充分必要条件是：它的部分和数列有上界。
2.
Theorem 1 ( bounded sum test ) a series of nonnegative terms converges if and only if it ' s partial sums are bounded above 定理2 (比较审敛法)设和都是正项级数，且。若级数收敛，则级数收敛；反之，若级数发散，则级数发散。
