已知tanα=1⼀7,tanβ=1⼀3,α,β∈(0,π⼀2),求α+2β的值 过程

2025-06-29 05:37:14
推荐回答(1个)
回答1:

tana=1/7,tanb=1/3
tan(a+b)
=(tana+tanb)/(1-tanatanb)
=(1/7+1/3)/(1-1/21)
=1/2.
tan(a+b+b)
=[tan(a+b)+tanb]/[1-tan(a+b)tanb]
=(1/2+1/3)/(1-1/2*1/3)
=1
因为:
0<β<π/2 ,所以:0<2β<π
(α值的范围不知)
α+2β=π/4或者α+2β=5π/4.