如图所示是函数f(x)=x^3+bx^2+cx+d的大致图象,则x1+x2=

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如图所示是函数f(x)=x^3+bx^2+cx+d的大致图象,则x1+x2=
如图所示是函数f(x)=x^3+bx^2+cx+d的大致图象,则x1+x2=

如图所示是函数f(x)=x^3+bx^2+cx+d的大致图象,则x1+x2=
f(0) = d = 0
f(-1) = -1 + b - c + d = 0
f(2) = 8 + 4b + 2c + d = 0
b = -1 ,c= -2 ,d = 0
f(x) = x³ - x² -2x
f'(x) = 3x² - 2x -2
3x² - 2x - 2 = 0
x1 + x2 = 2/3