cos(a+b)=-1,tan a =2 cot b=?
问题描述：
cos(a+b)=-1,tan a =2 cot b=?
答
cos(a+b)=-1,
sin(a+b)=0
tan(a+b)=0
tan(a+b)=(tana+tanb)/(1-tanatanb)=0
tana+tanb=0
2+tanb=0
tanb=-2
cotb=-1/2