这个极限怎么求？

1

tanx的周期为π

3
　　　--time together is just never quite enough.

洛必达法则

1/3?

答案为1

im tanx/tan3x
=lim ( 1/cosx^2) / (3/cos3x^2)
= lim (cos3x^2)/3cosx^2
= lim 6cos3x(-sin3x)/6cosx(-sinx)
= lim sin6x/sin2x
= lim 6cos6x/2cos2x
= -6 / -2 = 3　 This is a tail who waters exp.
这是一条会水经验的小尾巴。→ →