∵sin（

π

2

±θ）=cosθ，cos（π-θ）=-cosθ，sin（π-θ）=sinθ
∴原式=

cosθ+cosθ

cosθ−sinθ

=

2

1− sinθ cosθ

=

2

1−tanθ

=

2

1−2

=-2
故答案为：-2