tanx+tany=25 cotx+coty=30,那么tan(x+y)=?

分类: 作业答案 • 2021-12-20 05:55:11

问题描述：

答

cotx+coty
=1/tanx+1/tany
=(tanx+tany)/(tanxtany)
=30
所以 tanxtany=25/30=5/6
所以 tan(x+y)=(tanx+tany)/(1-tanxtany)=25/(1-5/6)=150

答

cotx+coty=30
1/tanx +1/tany=30
(tanx+tany)/tanxtany=30
25/tanxtany=30
tanxtany=25/30=5/6,
tan(x+y)
=(tanx+tany)/(1-tanxtany)
=25/(1-5/6)
=150