Question

sa se determine functia f de gradul al doilea daca f(-1)=1 , f(0)=1 si f(1)=3 .

Answer 1

f(x)=ax²+bx+c
f(-1)=a-b+c=1
f(0)=c=1
f(1)=a+b+c=3    
inlocuim pe c in prima si a treia relatie
a-b+1=1⇒a-b=0⇒a=b
a+b+1=3⇒a+b=2
scadem cele doua relatii⇒2a=2⇒a=1, b=2
f(x)=x²+2x+1