\[
 - \int {\frac{{dt}}{{\sqrt {3\left[ {\frac{4}{9} - \left( {t - \frac{1}{3}} \right)^2 } \right]} }}}  =  - \int {\frac{{dt}}{{\sqrt {\frac{4}{9} - \left( {t - \frac{1}{3}} \right)^2 } }}}  =  - \frac{1}{{\sqrt 3 }}\int {\frac{{dt}}{{\sqrt {\frac{4}{9} - \left( {t - \frac{1}{3}} \right)^2 } }}}  \to smena\left| \begin{array}{l}
 t - \frac{1}{3} = \frac{2}{3}z \\ 
 dt = \frac{2}{3}dz \\ 
 \end{array} \right|
\]