\input{preamble-standalone.ltx} \begin{document} % Ex. No. 137 (Section 17.9.1 : \tkzcname{tkzFillPolygon}) \begin{tikzpicture}[scale=0.7] \tkzInit[xmin=-3,xmax=6,ymin=-1,ymax=6] \tkzDrawX[noticks] \tkzDrawY[noticks] \tkzDefPoint(0,0){O} \tkzDefPoint(4,2){A} \tkzDefPoint(-2,6){B} \tkzPointShowCoord[xlabel=$x$,ylabel=$y$](A) \tkzPointShowCoord[xlabel=$x'$,ylabel=$y'$,% ystyle={right=2pt}](B) \tkzDrawSegments[->](O,A O,B) \tkzLabelSegment[above=3pt](O,A){$\vec{u}$} \tkzLabelSegment[above=3pt](O,B){$\vec{v}$} \tkzMarkAngle[fill= yellow,size=1.8cm,% opacity=.5](A,O,B) \tkzFillPolygon[red!30,opacity=0.25](A,B,O) \tkzLabelAngle[pos = 1.5](A,O,B){$\alpha$} \end{tikzpicture} \end{document}