1} (1-x)tg \frac{\pi*x}{2}" alt="lim_{x->1} (1-x)tg \frac{\pi*x}{2}" align="absmiddle" class="latex-formula">
1; x=t+1; t->0" alt="x-1=t, x->1; x=t+1; t->0" align="absmiddle" class="latex-formula">
0} -t *tg \frac{\pi*(t+1)}{2}" alt="lim_{t->0} -t *tg \frac{\pi*(t+1)}{2}" align="absmiddle" class="latex-formula">
0}-t*tg(\frac{\pi*t}{2}+\frac{\pi}{2})" alt="lim_{t->0}-t*tg(\frac{\pi*t}{2}+\frac{\pi}{2})" align="absmiddle" class="latex-formula">
0} -t*(-ctg \frac{\pi*t}{2})=" alt="lim_{t->0} -t*(-ctg \frac{\pi*t}{2})=" align="absmiddle" class="latex-formula">
0}\frac{2}{\pi}*\frac{\frac{\pi*t}{2}}{tg \frac{\pi*t}{2}}=" alt="lim_{t->0}\frac{2}{\pi}*\frac{\frac{\pi*t}{2}}{tg \frac{\pi*t}{2}}=" align="absmiddle" class="latex-formula">
