limx趋向于∞ (a+1)x^3+bx^2+2/2x^2+x+1=-2,求a,b的值.

limx趋向于∞ (a+1)x^3+bx^2+2/2x^2+x+1=-2,求a,b的值.
limx趋向于∞ (a+1)x^3+bx^2+2/2x^2+x+1=-2,求a,b的值.

limx趋向于∞ (a+1)x^3+bx^2+2/2x^2+x+1=-2,求a,b的值.
lim(x->∞)[(a+1)x^3+bx^2+2] /[2x^2+x+1 ]=-2
a+1 =0
=> a=-1
and
b/2 = -2
b= -4