3) arcsin 1 - 2arccos(-√2/2):

Математика. $$arcsin(1) - 2 \cdot arccos(-\frac{\sqrt{2}}{2}) = \frac{\pi}{2} - 2 \cdot \frac{3\pi}{4} = \frac{\pi}{2} - \frac{6\pi}{4} = \frac{\pi}{2} - \frac{3\pi}{2} = \frac{-2\pi}{2} = -\pi$$ Ответ: $$\frac{-\pi}{2}$$