soal um unj 2012 , tolong ya

[tex]\displaystyle r=\frac{u_2}{u_1}\\r=\frac{\left(\frac{x-1}{x+1}\right)^2}{\left(\frac{x-1}{x+1}\right)^2}\\r=\frac{x-1}{x+1}\\\\\text{Agar deret konvergen, maka haruslah}\\-1\ \textless \ r\ \textless \ 1\\-1\ \textless \ \frac{x-1}{x+1}\ \textless \ 1\\\\\frac{x-1}{x+1}\ \textgreater \ -1\\\frac{x-1}{x+1}+1\ \textgreater \ 0\\\frac{2x}{x+1}\ \textgreater \ 0\\\text{HP}_1=\{x|x\ \textless \ -1\vee x\ \textgreater \ 0\}\\\\\frac{x-1}{x+1}\ \textless \ 1\\\frac{x-1}{x+1}-1\ \textless \ 0\\\frac{-2}{x+1}\ \textless \ 0\\\frac{2}{x+1}\ \textgreater \ 0\\\text{HP}_2=\{x|x\ \textgreater \ -1\}\\\\\text{HP}=\text{HP}_1\cap\text{HP}_2\\\boxed{\boxed{\text{HP}=\{x|x\ \textgreater \ 0,x\in\mathbb{R}\}}}[/tex]