先求 (1+tanθ)(1+tan(π/4-θ))=1+tanθ*tan(π/4-θ)+tanθ+tan(π/4-θ)由于1=tan(π/4)=tan(π/4-θ+θ)=[tanθ+tan(π/4-θ)]/[1-tanθ*tan(π/4-θ)]得到tanθ*tan(π/4-θ)+tanθ+tan(π/4-θ)=1所以上式=2原...