Z góry dzięki za pomoc.
| 9 | ||
cos2(3x) = − | sprzeczność (dlaczego?) | |
| 2 |
| π | ||
3x = | + k * π | |
| 2 |
| π | π | |||
x = | + k * | |||
| 6 | 3 |
| π | ||
x = | ∊ [0 ; π] | |
| 6 |
| π | π | π | ||||
x = | + | = | ∊ [0 ; π] | |||
| 6 | 3 | 2 |
| π | π | 5 | ||||
x = | + 2 * | = | π ∊ [0 ; π] | |||
| 6 | 3 | 6 |
| π | π | |||
x = | + 3 * | > π więc nie należy do przedziału [0 ; π] | ||
| 6 | 3 |
| π | π | 5 | ||||
x ∊ { | ; | ; | π} | |||
| 6 | 2 | 6 |