Page 147 - Fixtures
P. 147
@ @pbjïØ Üa@ @QSR
:
C(n,k − 1) + C (n,k) = n ! + n !
(k − 1)!(n − k + 1)! k !(n − k)!
= n ! (k − 1 k + 1)! + k 1
1)!(n − !(n − k)!
= n ! k +n − k +1
k !(n − k + 1)!
= n !(n + 1)
k !(n − k + 1)!
= (n + 1!)
k !(n − k + 1)!
= C (n + 1,k)
a ∈A n +1 A:
k
kA . B = A − {a}
A, .C(n + 1,k)
(B ) k −1 a
.a B k
k −1 B C(n,k − 1)
ak A
A C(n,k − 1)
, .C(n,k) a k
.C(n + 1,k) = C(n,k − 1) + C(n,k)
