Anonymous

\begin{tabular}{|c|c|c|c|c|c|c|c|}
\hline
t   &  0 &\frac{\pi}{6}   &\frac{\pi}{4}   &\frac{\pi}{3}   &\frac{\pi}{2} &\frac{2\pi}{3}  &\frac{3\pi}{4}.\\ 
\hline
cost&  1 &\frac{\sqrt3}{2}&\frac{\sqrt2}{2}&\frac{1}{2}     &       0      &-\frac{1}{2}    &\frac{\sqrt2}{2}.\\ 
\hline
sint&  0 &\frac{1}{2}     &\frac{\sqrt2}{2}&\frac{\sqrt3}{2}&        1     &\frac{\sqrt3}{2}&\frac{\sqrt2}{2}.\\ 
\hline
\hline
\end{tabular}