| π |
| 4 |
| tana+1 |
| 1−tana |
| 1 |
| 3 |
∴tana=-
| 1 |
| 2 |
因此，
| (sina−cosa)2 |
| cos2a |
| sin2a−2sinacosa+cos2a |
| cos2a−sin2a |
分子分母都除以cos2a，得
| (sina−cosa)2 |
| cos2a |
| tan2a−2tana+1 |
| 1−tan2a |
故答案为：3
| π |
| 4 |
| 1 |
| 3 |
| (sina−cosa)2 |
| cos2a |
| π |
| 4 |
| tana+1 |
| 1−tana |
| 1 |
| 3 |
| 1 |
| 2 |
| (sina−cosa)2 |
| cos2a |
| sin2a−2sinacosa+cos2a |
| cos2a−sin2a |
| (sina−cosa)2 |
| cos2a |
| tan2a−2tana+1 |
| 1−tan2a |