$\left\{\begin{matrix}\\t\in \mathrm{R}\setminus \frac{1}{|a|}\text{, }a\neq 0,-\frac{1}{|a|}\text{, }a\neq 0\text{, }s=\frac{tv_{1}}{1-\left(at\right)^{2}}\text{, }v_{1}\in \mathrm{R}\text{, }a\neq 0\text{; }t\in \mathrm{R}\text{, }s=tv_{1}\text{, }v_{1}\in \mathrm{R}\text{, }a=0\text{, }&\text{unconditionally}\\t=\frac{1}{|a|}\text{, }s\in \mathrm{R}\text{, }v_{1}=0\text{, }a\neq 0\text{; }t=-\frac{1}{|a|}\text{, }s\in \mathrm{R}\text{, }v_{1}=0\text{, }a\neq 0\text{, }&a\neq 0\end{matrix}\right.$