b 6. b 西9b2a1b3 3b a,b,a, b a,b (5)比值[达朗贝尔 D' Alembert)判别法 K(K>0)当k>K有 A<p(p<则∑/绝对收敛 k=0M 3 3 0 3 1 3 2 3 3 2 2 0 2 1 2 2 2 3 1 1 0 1 1 1 2 1 3 0 0 0 0 1 0 2 0 3 0 1 2 3 ... a a b a b a b a b a a b a b a b a b a a b a b a b a b a a b a b a b a b b b b b (5).比值[达朗贝尔(D’Alembert)]判别法 "K (K > 0),当 k > K有 ( ) 则 å 绝对收敛 ¥ = + < < 0 1 1 , k k k k f f f r r