| 1 | ||
sin4 a + cos4 a=1− | sin22a | |
| 2 |
| 1 | ||
L = (sin2a + cos2a)2 − 2sin2acos2a = 1 − 2(sinacosa)2= 1 − 2( | sin2a)2 =
| |
| 2 |
| 1 | 1 | |||
= 1 − 2 | sin22a = 1 − | sin22a = P | ||
| 4 | 2 |
| 1 | ||
L = sin4α + cos4α = (sin2α + cos2α)2 − 2sin2αcos2α = 1 − | * 4sin2αcos2α = 1 − | |
| 2 |
| 1 | 1 | |||
(sin2α)2 = 1 − | sin22α = P | |||
| 2 | 2 |
| 1 | ||
sinxcosx = | sin2x , bo sin2x = 2sinxcosx | |
| 2 |
| 2 | ||
tg a + ctg a= | ||
| sin2a |
| six | cosx | sin2x + cos2x | 1 | 2 | ||||||
⇔ | + | = | = | = | ||||||
| cosx | sin | sinxcosx | 0.5sin2x | sin2x |
| a | 1−cosa | |||
tg | = | |||
| 2 | sina |