如题所述
第1个回答 2015-08-13
tan(A+B) =(tanA+tanB)/(1-tanAtanB) tan2A =2tanA/(1-2tanA)
tan(a+2b) =(tana+tan2b)/(1-tanatan2b)=
(tana+2tanb/(1-2tanb))/(1-tana(2tanb/(1-2tanb)))=(1/7+2*1/3/(1-2/3))/(1-1/7(2/3/(1-2/3)))=8/7/4/7=2
a+2b=argtan2本回答被提问者和网友采纳
tan(a+2b) =(tana+tan2b)/(1-tanatan2b)=
(tana+2tanb/(1-2tanb))/(1-tana(2tanb/(1-2tanb)))=(1/7+2*1/3/(1-2/3))/(1-1/7(2/3/(1-2/3)))=8/7/4/7=2
a+2b=argtan2本回答被提问者和网友采纳