= x^2 - \left( {\frac{1}
{2} - \frac{2}
{{\pi ^2 }}} \right) - \frac{{x - \frac{1}
{2}}}
{{\frac{1}
{{2\pi }} - \frac{4}
{{\pi ^3 }}}}\left( {\int_0^1 {x^3 \sin \left( {\pi x} \right)dx} - \frac{1}
{2}\left( {\frac{1}
{\pi } - \frac{4}
{{\pi ^3 }}} \right)} \right)