1.f(π/9)=tan(π/3+π/4)=(tanπ/3+tanπ/4)/(1-tanπ/3tanπ/4)=(√3+1)/(1-√3)=-√3-22.∵f(a/3+π/4)=2 ∴tan(a+3π/4+π/4)= tan(π+a)=tana=2sina/cosa=2sina=2cosa代入sin²a+cos²a=1cos²a=1/...