Knowing that $${\mathtt{tanx}} = {\mathtt{\,-\,}}{\frac{{\sqrt{{\mathtt{2}}}}}{{\mathtt{4}}}}$$, and pi/2 < x < pi, find out:
$${\mathtt{cos2x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{sen2x}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{4}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{2}}}}}{{\mathtt{9}}}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{11}}}{{\mathtt{9}}}}$$ .
