Question

Care dintre punctele :A( -1;0). B(1/2;3). C(1;5). Se afla pe Gf f:R->R f(x) =2x+2

Answer 1

A(-1;0) apartine Gf, daca f(-1)=0
adica: f(-1)=2(-1)+2=-2+2=0 insemna ca punctul A(-1,0) apartine Gf
B(1/2,3) apartine Gf daca f(1/2)=3
adica: f(1/2)=2(1/2)+2=1+2=3 insemna ca B(1/2,3) apartine Gf
C(1,5) apartine Gf daca f(1)=5
adica f(1)=2*1+2=4, dar 4 diferit de 5, insemna ca punctul C(1,5) nu apartine Gf
inseamna ca doar A si B apartin Gf