是-2
solution:
lim[x→-8] [√(1-x)-3]/[2+x^(1/3)]
分子有理化:
[√(1-x)-3][√(1-x)+3]=(1-x)-9=-(x+8)
分母有理化:[2+x^(1/3)][4-2x^(1/3)+x^(2/3)]
=8+x
分子分母相约8+x
=lim[x→-8] -[4-2x^(1/3)+x^(2/3)]/[√(1-x)+3]
=- [4-2(-8)^(1/3)+(-8)^(2/3)]/[√(1-(-8))+3]
=- (4-(-4)+4)/(3+3)
=-12/6
=-2
2