Question

polinomul f=x^3+2x^2-5x+m m apartine lui R are radacinile x1,x2 si x3

a) calculati x1^2+X2^2+x3^2

Answer 1

X1^2+x2^2+x3^2=S1^2+2S2

S1: x1+x2+x3= -b/a = -2

S2: x1x2+x1x3+x2x3= c/a= -5

Atunci X1^2+x2^2+x3^2=S1^2+2S2

(-2)^2 -2•(-5)=4 +10 =14

Answer 2

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