若tana(a+b)=2/5,tan(a-π/4)=1/4,则tan(b+π/4)的值等于
问题描述:
若tana(a+b)=2/5,tan(a-π/4)=1/4,则tan(b+π/4)的值等于
答
b+π/4=(a+b)-(a-π/4)
所以,tan(b+π/4)=[tan(a+b)-tan(a-π/4)]/[1+tan(a+b)tan(a-π/4)]
=(2/5-1/4)/(1+1/10)
=3/22