Question

x 趋近于π/2时,lim（sinx-1）tanx怎么求.尽量将思路过程说清楚点，谢谢

Answer 1

=lim(sinx-1)/cotx
0/0洛必达法则
=limcosx/-csc²x
=0
或者最简单的三角函数变换
=lim(sin²x-1)tanx/(sinx+1)
=lim-cosxsinx/(sinx+1)
=0/2