| x | ||
1 + cosx + cos | =0 | |
| 2 |
| x | x | x | ||||
1+cos2 | −sin2 | +cos | =0⇔ | |||
| 2 | 2 | 2 |
| x | x | x | x | x | ||||||
cos2 | +sin2 | +cos2 | −sin2 | +cos | =0 | |||||
| 2 | 2 | 2 | 2 | 2 |
| x | x | |||
2cos2 | +cos | =0 | ||
| 2 | 2 |
| x | x | |||
cos | *(2cos | +1)=0 | ||
| 2 | 2 |
| x | x | |||
cos | =0 lub (2cos | +1)=0⇔ | ||
| 2 | 2 |
| x | x | 1 | ||||
cos | =0 lub cos | =− | ||||
| 2 | 2 | 2 |
| x | π | x | π | x | π | ||||||
= | +kπ lub | =π− | +2kπ lub | =π+ | +2kπ⇔ | ||||||
| 2 | 2 | 2 | 3 | 2 | 3 |
| 4π | 8π | |||
x=π+2kπ lub x= | +4kπ lub x= | +4kπ | ||
| 3 | 3 |