\[\begin{array}{l} {\text{Радиус кривизны кривой }}\left( {x\left( t \right);y\left( t \right)} \right){\text{ равен}} \hfill \\ R = \left| {\frac{{{{\left( {{{\left( {x'} \right)}^2} + {{\left( {y'} \right)}^2}} \right)}^{\frac{3}{2}}}}}{{x'y'' - y'x''}}} \right|. \hfill \\ \end{array}\]