| 1 | ||
cos3x = | ||
| 2 |
| 1 | ||
cos(3x)= | ||
| 2 |
| π | π | |||
3x= | +2kπ lub 3x=− | +2kπ i k∊C i x∊(−2π,2π) | ||
| 3 | 3 |
| π | 2kπ | π | 2kπ | |||||
x= | + | lub x=− | + | i k∊C i x∊(−2π,2π) | ||||
| 9 | 3 | 9 | 3 |
| π | π | |||
x= | lub x=− | |||
| 9 | 9 |
| π | 6π | π | 6π | |||||
x= | + | lub x=− | + | ⇔ | ||||
| 9 | 9 | 9 | 9 |
| 7π | 5π | |||
x= | lub x=− | |||
| 9 | 9 |
| π | 4π | π | 12π | 13 | π | 4π | 11π | |||||||||
x= | + | = | + | = | lub x=− | + | = | |||||||||
| 9 | 3 | 9 | 9 | 9 | 9 | 3 | 9 |
| π | 2*3π | π | π | 17π | ||||||
x= | + | = | +2π∉D lub x=− | +2π= | ∊D | |||||
| 9 | 3 | 9 | 9 | 9 |