已知sin(X+Y)=2/3,sin(X-Y)=1/5,求(tanX)/(tanY)的值
人气：138 ℃ 时间：2020-03-19 11:14:15
解答
(tanX)/(tanY)=（sinX/cosX）/(sinY/cosY)=(sinXcosY)/(cosXsinY)又sinXcosY=（1/2）[sin(X+Y)+sin(X-Y)]=（1/2）[(2/3)+(1/5)]=13/30cosXsinY=（1/2）[sin(X+Y)-sin(X-Y)]=（1/2）[(2/3)-(1/5)]=7/30代入原式,得(ta...
推荐
- 已知sin(x+y)=1/3,sin(x-y)=1/5,则tanx/tany
- 已知sin(x+y)=1/2,sin(x-y)=1/3,求tanx,tany
- 若sin（x+y）=1/2,sin（x-y）=1/3,则tanx/tany等于?
- 证明 (tanX+tanY)/(tanX-tanY)=(sin(X+Y))/(sin(X-Y))
- 实数x，y满足tanx=x，tany=y，且|x|≠|y|，则sin(x+y)x+y−sin(x−y)x−y=_．
- 对西部的感受50字急!8：30以前快
- This pair of shoes cost
- 两筐苹果的重量比是9:8,从甲筐中取出24千克放入乙筐,则甲、乙重量比是3:4,问甲乙共多少千克.
猜你喜欢
