X趋向0 lim(xsinx)/(1-cosx)

问题描述:

X趋向0 lim(xsinx)/(1-cosx)
1/1/2=2那么7/2/4为什么等于7/8呢?

X趋向0 lim(xsinx)/(1-cosx)
=X趋向0 lim(xsinx)(1+cosx)/(1-cos^2x)
=X趋向0 limx(1+cosx)/sinx)
=X趋向0 lim(1+cosx)[x/sinx)]=2