来自邵瑞华的问题
组合题:C(k,i)+C(k,i-1)=C(k+1,i),
组合题:C(k,i)+C(k,i-1)=C(k+1,i),
1回答
2020-03-30 09:38
组合题:C(k,i)+C(k,i-1)=C(k+1,i),
组合题:C(k,i)+C(k,i-1)=C(k+1,i),
C(k,i)+C(k,i-1)=C(k+1,i),
C(k,i)+C(k,i-1)
=P(k,i)/P(i,i)+P(k,i-1)/P(i-1,i-1)
=[P(k,i)+iP(k,i-1)]/P(i,i)
=P(k+1,i)/P(i,i)
=C(k+1,i),