Question

Se da multimea A = {1,2,3,4,5,6,7}. Determinati numarul submultiplilor de doua elemente ale multimii A, astfel incat suma elementelor fiecareia sa fie un nr. par.
.Se dau multimile A = {x|x = 5n + 7, n ∈ N} si B = {y|y = $n^{2}$ , n ∈ N}. Determinati elementele multimilor C= { x ∈ A| x < 30} si D ={ y ∈ B| 30 < y < 100 }

Answer 1

1)Submultimile sunt:
{1,3},{1,5},{1,7},
{2,4},{2,6},
{3,5},{3,7},
{4,6},
{5,7}.
In concluzie sunt 9 submultimi.

2)Elementele multimii A sunt:
5*0+7=7
5*1+7=12
5*2+7=17
5*3+7=22
5*4+7=27
5*5+7=32
....
Multimea C={7,12,17,22,27}


Elementele multimii B sunt:
[tex]0^2=0\\ 1^2=1\\ 2^2=4\\ 3^2=9\\ 4^2=16\\ 5^2=25\\ 6^2=36\\ 7^2=49\\ 8^2=64\\ 9^2=81\\ 10^2=100\\ 11^2=121\\ ....[/tex]
Multimea D={36,49,64,81}