1、
lim(x→0-)sinx/|x|
=lim(x→0-)sinx/(-x)
=-lim(x→0-)sinx/x
=-1
2、
lim(x→∞)(1-2/x)^2x
=lim(x→∞)[(1-2/x)^-x/2)]^(-4)
=e^(-4)
3、
lim(x→∞)[(5+3x)/3x]^(-x)
=lim(x→∞)[(1+5/3x]^(-x)
=lim(x→∞)[(1+5/3x)^(3x/5)]^(-5/3)
=e^(-5/3)
4、lim(x→0)(1+3x)^1/x
=lim(x→0)[(1+3x)^(1/3x)]^3
=e^3