Solucionar r_{n}x^2leqyleqr_{t}

$$r _ { n } x ^ { 2 } \leq y \leq r _ { t }$$

Resolver para x

$$\left\{\begin{matrix}x\in \mathrm{R}\text{, }&(y\geq 0\text{ and }r_{n}=0\text{ and }y\leq r_{t})\text{ or }(y>0\text{ and }r_{n}\leq 0\text{ and }y\leq r_{t})\text{ or }(r_{t}\geq 0\text{ and }r_{n}<0\text{ and }y=0)\\x\in (-\infty,-\sqrt{\frac{y}{r_{n}}}]\cup [\sqrt{\frac{y}{r_{n}}},\infty)\text{, }&y\leq 0\text{ and }r_{n}<0\text{ and }y\leq r_{t}\\x=-\sqrt{\frac{y}{r_{n}}}\text{; }x=\sqrt{\frac{y}{r_{n}}}\text{, }&(y\geq 0\text{ and }r_{n}>0\text{ and }y\leq r_{t})\text{ or }(r_{t}\geq 0\text{ and }r_{n}<0\text{ and }y=0)\\x\in [-\sqrt{\frac{y}{r_{n}}},\sqrt{\frac{y}{r_{n}}}]\text{, }&y\geq 0\text{ and }r_{n}>0\text{ and }y\leq r_{t}\end{matrix}\right,$$

Resolver para y

$$y\in \begin{bmatrix}r_{n}x^{2},r_{t}\end{bmatrix}\text{, }r_{n}\leq \frac{r_{t}}{x^{2}}$$