Respuesta :

[tex]y=\ln (x-1)\\ D:x\ \textgreater \ 1\\\\ \displaystyle \lim_{x\to1^+}\ln (x-1)=\ln 0^+=-\infty [/tex]

So the asymptote is [tex]x=1[/tex]. This is right-sided asymptote. The left-sided doesn't exist because of the domain.