lim(cot(x)(1/sin(x)-1/x))=?当x->0时
问题描述：
lim(cot(x)(1/sin(x)-1/x))=?当x->0时
急.先谢
答
cot(x)(1/sin(x)-1/x)
=(cosx/sinx)((x-sinx)/xsinx)
=(1-xx/2)(x-sinx)/xsinxsinx
=(x-sinx-xxx/2+xxsinx/2)/xsinxsinx
=(x/sinx-1-xx/2+xx/2)/xsinx
=0/xsinx
=0