Question

Дам 50 баллов. помогите решить задачку. пожалуйста.​

Answer 1

Ответ:

$\dfrac{cos\frac{\pi}{30}\cdot cos\frac{\pi}{15}+sin\frac{\pi}{30}\cdot sin\frac{\pi}{15}}{sin\frac{7\pi}{30}\cdot cos\frac{4\pi}{15}+cos\frac{7\pi}{30}\cdot sin\frac{4\pi}{15}}+2\, sin\dfrac{\pi}{12}\cdot cos\dfrac{\pi}{12}=\\\\\\\\=\dfrac{cos(\frac{\pi}{30}-\frac{\pi}{15})}{sin(\frac{7\pi}{30}+\frac{4\pi}{15})}+sin(2\cdot \dfrac{\pi}{12})=\dfrac{cos(-\frac{\pi}{30})}{sin\frac{\pi}{2}}+sin\dfrac{\pi}{6}=cos\dfrac{\pi}{30}+\dfrac{1}{2}$