x = \pi n, n \in Z\\3. \\f(x) = \frac{1}{arccosx}\\ arccosx = 0 => x = 0" alt="1.\\f(x) = tg(x-\frac{\pi}{4})\\ x - \frac{\pi}{4} = \frac{\pi}{2} + \pi n, n \in Z\\x = -\frac{\pi}{4} + \pi n, n \in Z\\ 2.\\f(x) = \frac{1}{sinx}\\ sinx = 0 => x = \pi n, n \in Z\\3. \\f(x) = \frac{1}{arccosx}\\ arccosx = 0 => x = 0" align="absmiddle" class="latex-formula">