Liczby x1, x2 są różnymi rzeczywistymi pierwiastkami równania (m-1)x^2 +4mx +4m-2=0. Narysuj wykres funkcji
g(m) = ( x1 ^3 *x2 - x1*x2^3)(x1^3 + x1^2*x2- x1*x2^2-x2^3)^-1.​



Odpowiedź :

Hanka

[tex](m-1)x^2 +4mx +4m-2=0[/tex]

[tex]m \neq 1[/tex]

[tex]\Delta>0[/tex]

[tex]\Delta=(4m)^2-4\cdot(m-1)(4m-2)=16m^2-4(4m^2-2m-4m+2)=[/tex]

[tex]16m^2-16m^2+8m+16m-8=24m-8[/tex]

[tex]24m-8>0[/tex]

[tex]24m>8\ \ \ |:24[/tex]

[tex]m>\frac{1}{3}[/tex]

[tex]m\in \left(\frac{1}{3};+\infty \right) [/tex]

[tex]( x_1 ^3 \cdot x_2 - x_1\cdot x_2^3)(x_1^3 + x_1^2\cdot x_2- x_1\cdot x_2^2-x_2^3)^{-1}=[/tex]

[tex]\frac{x_1 ^3 \cdot x_2 - x_1\cdot x_2^3}{x_1^3 + x_1^2\cdot x_2- x_1\cdot x_2^2-x_2^3}=[/tex]

[tex]\frac{x_1x_2(x_1^2 - x_2^2)}{x_1^2(x_1 + x_2)- x_2^2( x_1+x_2)}=[/tex]

[tex]\frac{x_1x_2(x_1^2 - x_2^2)}{(x_1 + x_2)( x_1^2-x_2^2)}=[/tex]

[tex]\frac{x_1x_2}{x_1 + x_2}=\frac{\frac{c}{a}}{-\frac{b}{a}}=-\frac{c}{b}=-\frac{4m-2}{4m}=-1+\frac{1}{2m}=\frac{1}{2m}-1[/tex]

[tex]g(m)=\frac{1}{2m}-1[/tex]

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