R,=io,h房 1+(n-1) n [1+(n-1)r] 当家系足够大时: R-ia,总 2023/5/23 82023/5/23 8 + − + − = + − + − + − = = [1 ( 1) ] 1 ( 1) [1 ( 1) ] 1 ( 1) [1 ( 1) ] 2 2 2 n n r n r h i h n r n r n n i R i h A P A P f f f R i h r r f P A = 2 当家系足够大时: