Nie rozumie co jest nie tak.
a = √7
b = √3
c = √a2−b2=2
Obliczam: bez wykorzystywania wzorów..
a) 4sin2α * cos2α + tg2α * ctg2α=
| c | √3 | c | √3 | |||||
4( | )2 * ( | )2 + ( | )2 * ( | )2= | ||||
| √7 | √7 | √3 | c |
| c2 | 3 | c2 | 3 | |||||
4 | * | + | * | = | ||||
| 7 | 7 | 3 | c2 |
| c2 | 3 | 12 c2 | ||||
4 | * | = | ||||
| 7 | 7 | 49 |
| 12 c2 | 12 *4 | 48 | 48 | |||||
= | = | <<<< w książce jest : 1 | ||||||
| 49 | 49 | 49 | 49 |
| 2 | c | |||
b) (sinα + tgα)2 = ( | * | )2 = | ||
| √7 | √3 |
| 12 + 4c + 7 c2 | 12+8+28 | 27 | ||||
= | = 1 | <<<<<To juz calkiem źle c | ||||
| 21 | 21 | 21 |
| c2 | 3 | |||
4* | * | +1= (opuściłeś ten składnik sumy) | ||
| 7 | 7 |
| 12c2 | 48 | |||
= | +1=1 | |||
| 49 | 49 |
| c2 | 3 | |||
a)...+ | * | =.....+1, zgubiłęś tą jedynkę | ||
| 3 | c2 |
.
| c | c | 2 | 2 | |||||
( | + | )2=( | + | )2= wzór skróconego mnożenia(a+b)2=a2+2ab+b2 | ||||
| a | b | √7 | √3 |
| 4 | 8 | 4 | 4 | 4 | 8√21 | |||||||
= | + | + | = | + | + | = | ||||||
| 7 | √21 | 3 | 7 | 3 | 21 |
| 12+28 | 8√21 | |||
= | + | = dokończ | ||
| 21 | 21 |
Moim skromnym zdaniem powinieneś dostać bana
.
| 3 | c2 | 3 | ||||
W przykladzie a po drodze zgubiles 1 bo | =1 tam gdzie masz | * | ||||
| 3 | 3 | c2 |
| 2 | 2 | 2√3+2√7 | (2√3+2√7)2 | |||||
( | + | )2=( | )2= | = | ||||
| √7 | √3 | √21 | (√21)2 |
| 12+8√21+28 | 40+8√21 | ||
= | |||
| 21 | 21 |