2. · (k+1)2 k2. → 1. 2. ∑ 1 k! converges: ak+1 ak. = 1 k+1. → 0. ∑ k. 10k converges: ak+1 ak. = 1. 10. · k+1 k. → 1. 10. ∑ kk k! diverges: ak+1.
確定! 回上一頁