Question

REPEDE!!!!!!!DAU COROANA!!!!!!!!!!!!!!!!

Fie A sii B 2 multimi.Cunoscand:
a.card(A reunit B)=16,card A=6,card B=8,calculati card(A intersectie B)
b.card A=12 si card(A-B)=4,calculati card(A intersectie B)
c.B este submultime a lui A,calculati A intersectie B

Answer 1

a)folosim relatia
card( A∪B)=cardA +cardB-card (A∩B)
16=6+8-card ( A∩B)
16=14-card ( A∩B)
card (A∩B)=-2 absurd
 pt orice multim vida sau finita X  avem cardX≥0, deci datele sunt  GRESITE

(pt ca problema sa aibe sens e necesar sa avem card A+card B≥card(A∪B);  aici 6+8<16, problema are date gresite)

b)card A=carda(A\B) + card (A∩B)
  12=4+ card (A∩B)
card (A∩B)=8

c)A∩B=B