=0;\\\pi*k <5(x-1) \leq \frac{\pi}{2}+\pi*k;\\\pi*k <5x-5 \leq \frac{\pi}{2}+\pi*k;\\\pi*k+5 <5x \leq 5+\frac{\pi}{2}+\pi*k;\\\frac{\pi*k}{5}+1<x \leq 1+\frac{\pi}{10}+\frac {pi*k}{5};\\" alt="ctg 5 *(x-1)>=0;\\\pi*k <5(x-1) \leq \frac{\pi}{2}+\pi*k;\\\pi*k <5x-5 \leq \frac{\pi}{2}+\pi*k;\\\pi*k+5 <5x \leq 5+\frac{\pi}{2}+\pi*k;\\\frac{\pi*k}{5}+1<x \leq 1+\frac{\pi}{10}+\frac {pi*k}{5};\\" align="absmiddle" class="latex-formula">
x э 
k є Z