作业帮sin（x+y)=1/2 ,sin(x-y)=1/3,求tanx/tany的值
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sin（x+y)=1/2 ,sin(x-y)=1/3,求tanx/tany的值
sin（x+y)=1/2 ,sin(x-y)=1/3,求tanx/tany的值
sin（x+y)=1/2 ,sin(x-y)=1/3,求tanx/tany的值
2sinxcosy=sin(x+y)+sin(x-y)=5/6
2cosxsiny=sin(x+y)-sin(x-y)=1/6
两式相除得所求=5
(tanX)/(tanY)=（sinX/cosX）/(sinY/cosY) =(sinXcosY)/(cosXsinY) 又sinXcosY=（1/2）[sin(X Y) sin(X-Y)] =（1/2）[(2/3) (1