Question

E functia de gradul 1

1)Fie:f:R->R, f(x)= 3x+5

a) calculati: (fof)(2), (fof)(0)
b) aflați punctele de intersectie cu axele de coordonate.

Answer 1

a) (fof)(2)= f( f(2) ) =3× (f(2))+5 =
=3(3×2+5)+5=
=3×11+5=38

(fof)(0)= f( f(0) ) =
=3× (f(0)) +5=
= 3(3×0+5)+5=
= 3×5+5=20


b) Gf intersectat cu axa OX=>f(x)=0
=> 3x+5=0=
=3x= -5
= -5 supra 3
=> A(-5supra 3 ; 0)

Gf intersectat cu axa OY=> x=0
=>3×0+5=5
=>B( 0;5)

Baftă!