Question

Fie M={0,1,2...10}. Det. nr. submultimilor lui M care contin el. 0 si 10.
// Stiu ca numarul de submultimi este 2^n=2^11=2048.

Answer 1

{0,10}⊂M -1 submultime=$C_9^0$
{0,10,a_1} unde a_1∈{1,2,...,9} adica 9 submultimi=$C_9^1$ submultimi
{0,10,a_1,a_2} unde a_1,a_2∈{1,2,...,9} adica $C_9^2$ submultimi
.............................................
{0,10,a_1,...,a_9} unde a_1,..., a_9∈{1,2,...,9} adica $C_9^9$ submultimi
Total submultimi=$C_9^0+C_9^1+...+C_9^9=2^9=512 ~submultimi$