[3-√(5+4x)]/√x-1在x趋向于1时的极限.

问题描述:

[3-√(5+4x)]/√x-1在x趋向于1时的极限.

lim [3-√(5+4x)]/(√x-1)
=lim (4-4x)/{(√x-1)【3+√(5+4x)】}
=lim 4(1-√x)(1+√x)/[6(√x-1)]
=-4/3