题干
若 sin (x+
)=
，则 sin (
−x)sin 2
−x)+cos (2x+
)= ____．
| π |
| 6 |
| 1 |
| 4 |
| 5 |
| π |
| 6 |
| π |
| 3 |
| π |
| 3 |
