Question

Помогите вычислить по тригонометрии

Answer 1

Ответ:

$\frac{1}{4}$

Объяснение:

$\frac{2cos^{2} \alpha -(cos^{2}\alpha+sin^{2}\alpha)}{8\cdot \frac{sin(\frac{\pi}{4}-\alpha )}{cos(\frac{\pi}{4}-\alpha )} \cdot cos^{2}(\frac{\pi}{4}-\alpha )} =\frac{cos^{2}\alpha-sin^{2}\alpha}{8 \cdot sin(\frac{\pi}{4}-\alpha) \cdot cos(\frac{\pi}{4}-\alpha)} =\frac{cos2\alpha }{4sin(\frac{\pi }{2} -2\alpha )} =\frac{cos2\alpha}{4cos2\alpha } =\frac{1}{4}$