若a+b=п/4,则tana+tanb+tanatanb=______.
问题描述:
若a+b=п/4,则tana+tanb+tanatanb=______.
答
tan(a+b)=(tana+tanb)/(1-tanatanb)
tana+tanb=tan(a+b)*(1-tanatanb)=1-tanatanb
tana+tanb+tanatanb=1