求大神讲解一下谢谢了
2024-07-22 20:10:24作者：饭克斯
x->0
分母
cosx-1=-(1/2)x^2+o(x^2)
分子
(1+x^2+x^3)^(1/3)
=(1+x^2+o(x^2))^(1/3)
=1+(1/3)x^2+o(x^2)
(1+x^2+x^3)^(1/3)-1=(1/3)x^2+o(x^2)
lim(x->0)[(1+x^2+x^3)^(1/3)-1]/(cosx-1)
=lim(x->0)(1/3)x^2/[-(1/2)x^2]
=-2/3
ans:B
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