当x趋于0+时,lim (ln tan7x)/(ln tan2x)怎么求,

问题描述:

当x趋于0+时,lim (ln tan7x)/(ln tan2x)怎么求,

=lim (ln sin7x - ln cos7x)/(ln sin2x - ln cos2x)=lim (ln sin7x - 0)/(ln sin2x - 0)=lim (ln sin7x )/(ln sin2x )利用洛笔答法则得=lim (7·cos7x/ sin7x )/(2·cos2x/ sin2x )=lim (7·cos7x·sin2x)/( 2·sin7...