| π | π | |||
x≠ | +kπ, x≠ | +kπ/3, x≠kπ | ||
| 2 | 6 |
| sin3x | cosx | |||
a= | * | = | ||
| cos(3x) | sinx |
| 3sinx−4sin3x | cosx | |||
= | * | ⇔ | ||
| cos3x−3sin2xcosx | sinx |
| 3−4sin2x | ||
a= | ||
| cos2x−3sin2x |
| 3−4sin2x | ||
a= | ||
| 1−4sin2x |
| sin3x | ||
2) w= | =3−4sin2x | |
| sinx |
| 2+1−4sin2x | ||
a= | ||
| 1−4sin2x |
| 2 | ||
a= | +1 | |
| 1−4sin2x |
| 2 | ||
a−1= | ||
| 1−4sin2x |
| 2 | ||
1−4sin2x= | /+2 | |
| a−1 |
| 2 | ||
3−4sin2x= | +2 | |
| a−1 |
| sin3x | 2a | |||
w= | = | |||
| sinx | a−1 |