Преобразуй в произведение. $\sin\dfrac{\pi}{4}-\sin\dfrac{\pi}{5}$ $2\sin\dfrac{\pi}{20}\cos\dfrac{9\pi}{20}$ $2\sin\dfrac{9\pi}{40}\cos\dfrac{\pi}{40}$ $2\sin\dfrac{\pi}{40}\cos\dfrac{9\pi}{40}$ $2\cos\dfrac{9\pi}{40}\cos\dfrac{\pi}{40}$

Задание

Преобразуй в произведение.

\(\sin\dfrac{\pi}{4}-\sin\dfrac{\pi}{5}\)

Выбери верный вариант.

\(2\sin\dfrac{\pi}{20}\cos\dfrac{9\pi}{20}\)
\(2\sin\dfrac{9\pi}{40}\cos\dfrac{\pi}{40}\)
\(2\sin\dfrac{\pi}{40}\cos\dfrac{9\pi}{40}\)
\(2\cos\dfrac{9\pi}{40}\cos\dfrac{\pi}{40}\)