應是\(2x+3y\le 6\)
由餘弦定理可知\(\overline{OA}=\overline{OB}=\overline{AB}=\sqrt{7}\)
設向量OC=2向量OA，向量OD=3向量OB
所求即為
\(\begin{align}
& \Delta OCD-\Delta OAB \\
& =\frac{1}{2}\times 2\sqrt{7}\times 3\sqrt{7}\times \sin 60{}^\circ -\frac{1}{2}\times \sqrt{7}\times \sqrt{7}\times \sin 60{}^\circ \\
& =\frac{35}{4}\sqrt{3} \\
\end{align}\)
