首先，求出tanθ＝-3/2然后，tan(θ-π/4)＝（tanθ-tanπ/4）/（1-tanθ×tanπ/4）代入tanθ＝-3/2，tanπ/4＝1，得，答案是-1
tanθ = -3/2tan(θ-π/4)=[tanθ - tan(π/4)]/[1+tanθ .tan(π/4)]=( -3/2 -1) /( 1- 3/2)=-(5/2)/(-1/2)=5ans : A
