tanθ=2，则sin(π2+θ)−cos(π−θ)sin(π2−θ)−sin(π−θ)

∵sin（π2±θ）=cosθ，cos（π-θ）=-cosθ，sin（π-θ）=sinθ∴原式=cosθ+cosθcosθ−sinθ=21−sinθcosθ=21−tanθ=21−2=-2故答案为：-2