tan(π-x)=-1/2,则tan(π/4-x)=

问题描述:

tan(π-x)=-1/2,则tan(π/4-x)=

tan(π-x)=-tanx=-1/2
tanx=1/2
所以原式=(tanπ/4-tanx)/(1+tanπ/4tanx)
=(1+1/2)/(1-1/2)
=3