tanx=2,tan(x-y)=-3/5,则tany=?
问题描述：
tanx=2,tan(x-y)=-3/5,则tany=?
答
公式：tan(A-B)=(tanA-tanB)/(1+tanAtanB)
因tanx=2，tan(x-y)=-3/5
则tan(x-y)=(tanx-tany)/(1+tanxtany) =(2-tany)/(1+2*tany)=-3/5
由上式课解得tany= -13
答
tan(x-y)=(tanx-tany)/(1+tanxtany)
带入数据解题吧！tany=-13
答
tan(x-y)=(tanx-tany)/(1+tanxtany)
(2-tany)/(1+2tany)=-3/5
3+6tany=5tany-10
tany=-13