彐M,使得nx≤M(m=0,2,) n ax =a.x nO n ≤M 0 0 0 当<时,等比级数∑M收敛, 0 H=0 0 ∑anx"收敛,即级数∑a1x收敛; =0 =0 上页( 0,1,2, ) a x0 M n = n 使得 n M, n n n n n n x x a x a x 0 0 = n n n x x a x 0 0 = n x x M 0 1 , 0 当 时 x x , 0 0 等比级数 收敛 n n x x M = , 0 收敛 = n n an x ; 0 即级数 收敛 n= n an x