s=tanx＋tany=(sinx/cosx)＋(siny/cosy)=[sinxcosy＋cosxsiny]/[cosxcosy]=[sin(x＋y)]/[cosxcosy]=[(√3)/2]/{(1/2)[cos(x－y)＋cos(x＋y)]}=(√3)/[cos(x－y)＋1/2],要求s的最小值,只要求出cos(x－y)的最大值,易知...