Leysa y=sqrt{1+x/1-x}

$$y= \sqrt{ \frac{ 1+x }{ 1-x } }$$

Leystu fyrir x (complex solution)

$$x=-\frac{1-y^{2}}{y^{2}+1}$$

$$y\neq i\text{ and }\left(y=0\text{ or }arg(y)<\pi \right)\text{ and }y\neq -i$$

Leystu fyrir y (complex solution)

$$y=\sqrt{\frac{x+1}{1-x}}$$

$$x\neq 1$$

Leystu fyrir x

$$x=-\frac{1-y^{2}}{y^{2}+1}$$

$$y\geq 0$$

Leystu fyrir y

$$y=\sqrt{\frac{x+1}{1-x}}$$

$$x\geq -1\text{ and }x<1$$