§32.幂级数 0/54 法,能够确定级数(3.2-2)的收敛性 1.比值判别法 如果 k+1 k+1 Iz-zol Iakllz-zolk k-900ak <1,(3.2-2)收敛,(3.2-1)绝对收敛, >1,(322发散,(321发散 R= lim 32-3) →0 则 z-al<R,(32-2)收敛,(3.2-1)绝对收敛,(3,2-4) z-zo|>R,(3.2-2)发散,(3.2-1)发散 ● First●Prev●Next●Last● Go Back● Full screen●cose●Quit• First • Prev • Next • Last • Go Back • Full Screen • Close • Quit §3.2. ?ê 10/54 {. §U. . (. ½. ?. ê. (3.2-2). Â. ñ. 5. © 1. 'ŠO{ XJ ~ lim k→∞ |ak+1||z − z0| k+1 |ak||z − z0| k = lim k→∞     ak+1 ak     |z − z0| = ( < 1, (3.2-2)Âñ§(3.2-1)ýéÂñ, > 1, (3.2-2)uѧ(3.2-1)uÑ. - ~ R = lim k→∞     ak ak+1     , (3.2-3) K ~ |z − z0| < R , (3.2-2)Âñ§(3.2-1)ýéÂñ, (3.2-4) ~ |z − z0| > R , (3.2-2)uѧ(3.2-1)uÑ. (3.2-5)