Question

Fie A multimea numerelor naturale care se imparte la 4 ,iar B multimea numerelor naturale care au cifra unitatilor 5.Aflati A U B

Answer 1

A={4k l k∈N}  B={5k l k∈N}
AUB={4k,5k l k∈Z}=
Pyt  k=0  4*0=0  5*0=0
k=1  4*1=4  5*1=5
k=2
4*2=8, 5*2=10
s.a.m.d.
AUB={0,4,5,8,10...}