数学排列组合:C(m,n+1):C(m,n):C(m-2,n)=4:2:1求m,n值.m右上n右下角
问题描述:
数学排列组合:C(m,n+1):C(m,n):C(m-2,n)=4:2:1求m,n值.m右上n右下角
答
因为C(m,n+1)=C(m,n)+C(m-1,n) [C(m,n+1)]/C(m,n)=[C(m,n)+C(m-1,n)]/C(m,n) =1+C(m-1,n)/C(m,n)=4/2=2 所以C(m-1,n)=C(m,n) 所以(m-1)+m=2m-1=n; 所以 [C(m,n)]/[C(m-2,n)] =[C(m,2m-1)]/C(m-2,2m-1) =2/1 =2,C(m...