Задача 47616 Помогите)...

tema555

2020-04-20 09:48:53

Помогите)

sova

2020-04-20 10:09:20

6.
Формула:

[m]sin \alpha \cdot sin\beta =\frac{1}{2}sin ( \alpha+\beta)+ \frac{1}{2}sin ( \alpha-\beta)[/m]
[m]4sin \frac{13 \pi}{36} \cdot sin\frac{4 \pi}{36}=4\cdot \frac{1}{2}sin( \frac{13 \pi}{36}+ \frac{4 \pi}{36})+4\cdot \frac{1}{2} sin ( \frac{13\pi}{36}- \frac{4\pi}{36})=...[/m]

7.
Формула:

[m]cos \alpha \cdot cos \beta =\frac{1}{2}cos( \alpha+\beta)+ \frac{1}{2}cos( \alpha-\beta)[/m]

[m]2cos \frac{\pi}{18} \cdot cos\frac{5 \pi}{18}=2\cdot \frac{1}{2}cos( \frac{\pi}{18}+ \frac{5 \pi}{18})+2\cdot \frac{1}{2}cos( \frac{\pi}{18}- \frac{5\pi}{18})=...[/m]