sin(π−α)cos(2π−α)tan(−α+π) |
−tan(−α−π)sin(−π−α) |
sinαcosα(−tanα) |
tanαsinα |
(2)∵α为第三象限角,且cos(α-
3π |
2 |
1 |
5 |
∴sinα=-
1 |
5 |
∴cosα=-
1−sin2α |
2
| ||
5 |
则f(α)=-cosα=
2
| ||
5 |
sin(π−α)cos(2π−α)tan(−α+π) |
−tan(−α−π)sin(−π−α) |
3π |
2 |
1 |
5 |
sin(π−α)cos(2π−α)tan(−α+π) |
−tan(−α−π)sin(−π−α) |
sinαcosα(−tanα) |
tanαsinα |
3π |
2 |
1 |
5 |
1 |
5 |
1−sin2α |
2
| ||
5 |
2
| ||
5 |