If n and r are integers such that ` 1 le r le n` then `n. C (n-1,r-1)=`

n and r integers such that 1lerlen , then n. ""^(n-1)C_(r-1) is

If n and r are integers such that 1

IF n and r are positive inegers such that r le n then ""^(n) C_(r) + ""^(n)C_(r-1) =

If n and r are positive integers such that. 2 le r le n , show that overset(n) C_r+2 overset(n) C_{r-1}+overset(n) C_(r-2)=overset(n+2) C_r

If n and r are two positive integers such that nger,"then "^(n)C_(r-1)+""^(n)C_(r)=

Let n\ a n d\ r be no negative integers suych that rlt=n .Then, \ ^n C_r+\ ^n C_(r-1)=\ ^(n+1)C_r

Let n and r be no negative integers suych that r<=n. Then,^(n)C_(r)+^(n)C_(r-1)=^(n+1)C_(r)

If m,n,r are positive integers such that r lt m,n, then ""^(m)C_(r)+""^(m)C_(r-1)""^(n)C_(1)+""^(m)C_(r-2)""^(n)C_(2)+...+ ""^(m)C_(1)""^(n)C_(r-1)+""^(n)C_(r) equals

If m,n,r are positive integers such that r lt m,n, then ""^(m)C_(r)+""^(m)C_(r-1)""^(n)C_(1)+""^(m)C_(r-2)""^(n)C_(2)+...+ ""^(m)C_(1)""^(n)C_(r-1)+""^(n)C_(r) equals