Respuesta :
[tex]\\ \rm\hookrightarrow \dfrac{\sqrt{x+1}+\sqrt{x-1}}{\sqrt{x+1}-\sqrt{x-1}}+\dfrac{\sqrt{x+1}-\sqrt{x-1}}{\sqrt{x+1}+\sqrt{x-1}}[/tex]
[tex]\sf Let\begin{cases}\sf \sqrt{x+1}=a \\ \sf \sqrt{x-1}=b\end{cases}[/tex]
Now
[tex]\\ \rm\hookrightarrow \dfrac{a+b}{a-b}+\dfrac{a-b}{a+b}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{\left\{(a+b)(a+b)\right\}+\left\{(a-b)(a-b)\right\}}{(a+b)(a-b)}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{(a+b)^2+(a-b)^2}{a^2-b^2}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{a^2+2ab+b^2+a^2-2ab+b^2}{a^2-b^2}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{2a^2+2b^2}{a^2-b^2}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{2(a^2+b^2)}{a^2-b^2}[/tex]
Put values
[tex]\\ \rm\hookrightarrow \dfrac{2\left[(\sqrt{x+1})^2+(\sqrt{x-1})^2\right]}{(\sqrt{x+1})^2-(\sqrt{x-1})^2}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{2(x+1)(x-1)}{(x+1)(x-1)}[/tex]
- Take 2 common
[tex]\\ \rm\hookrightarrow 2\left(\dfrac{(x+1)(x-1)}{(x+1)(x-1)}\right)[/tex]
[tex]\\ \rm\hookrightarrow 2(1)[/tex]
[tex]\\ \rm\hookrightarrow 2[/tex]