Question

fie A={1,2,3,...., 78} Determinati nr submultimilor B ale lui A,stiiind ca {1,2,3,....,75} inclusa in B

Answer 1

Mai raman elementele 76, 77, 78.

C3(1)+C3(2)+C3(3)=

(3!)/(1! x 2!)+(3!)/(2!x1!)+(3!)/(3!x0!)=

6/2 +6/2 +6/6=3+3+1=7 submultimi

Unde am notat Cx(y) combinatii de x luate cate y.
''!"=factorial