由(3)可知直線\(L\)的方向向量\(\overrightarrow{d}=(0,-\sqrt{2},2)\),可設直線\(L\)的參數方程為\(\begin{cases}x = x_0 + 0t\\y = y_0-\sqrt{2}t\\z = z_0 + 2t\end{cases}\)(\(t\)為參數)。
又因為直線\(L\)上的點到原點距離為2(\(\vert\overrightarrow{OQ}\vert = 2\)),且\(\overrightarrow{OQ}\)與\(\overrightarrow{OA}\)、\(\overrightarrow{OB}\)夾角為\(60^{\circ}\) ,在(3)中已求得\(x = 1\),所以直線\(L\)的參數方程可寫為\(\begin{cases}x = 1\\y = y_0-\sqrt{2}t\\z = z_0 + 2t\end{cases}\)。
由\(\vert\overrightarrow{OQ}\vert = 2\),根據向量模長公式\(\vert\overrightarrow{OQ}\vert=\sqrt{x^{2}+y^{2}+z^{2}} = 2\),將\(x = 1\)代入可得\(1 + y^{2}+z^{2}=4\),即\(y^{2}+z^{2}=3\)。
把\(y = y_0-\sqrt{2}t\),\(z = z_0 + 2t\)代入\(y^{2}+z^{2}=3\)得\((y_0-\sqrt{2}t)^{2}+(z_0 + 2t)^{2}=3\)。
又由\(\overrightarrow{OQ}\cdot\overrightarrow{OA}=2\)(\(\overrightarrow{OQ}=(x,y,z)\),\(\overrightarrow{OA}=(1,\sqrt{2},1)\))可得\(x+\sqrt{2}y + z = 2\),把\(x = 1\)代入得\(\sqrt{2}y + z = 1\),即\(z = 1-\sqrt{2}y\)。
再由\(\overrightarrow{OQ}\cdot\overrightarrow{OB}=2\)(\(\overrightarrow{OB}=(2,0,0)\))可得\(2x = 2\),所以\(x = 1\)。
將\(z = 1-\sqrt{2}y\)代入\(y^{2}+z^{2}=3\)得\(y^{2}+(1-\sqrt{2}y)^{2}=3\),展開得\(y^{2}+1 - 2\sqrt{2}y + 2y^{2}=3\),整理得\(3y^{2}-2\sqrt{2}y - 2 = 0\)。
因式分解得\((\sqrt{3}y+\sqrt{2})(\sqrt{3}y - \sqrt{2}) = 0\),解得\(y_1=\frac{\sqrt{2}}{\sqrt{3}}\),\(y_2=-\frac{\sqrt{2}}{\sqrt{3}}\)。
當\(y=\frac{\sqrt{2}}{\sqrt{3}}\)時,\(z = 1-\frac{2}{\sqrt{3}}\);當\(y = -\frac{\sqrt{2}}{\sqrt{3}}\)時,\(z = 1+\frac{2}{\sqrt{3}}\)。
所以\(Q\)點坐標為\((1,\frac{\sqrt{2}}{\sqrt{3}},1 - \frac{2}{\sqrt{3}})\)和\((1,-\frac{\sqrt{2}}{\sqrt{3}},1+\frac{2}{\sqrt{3}})\) ,化簡為\((1,\frac{\sqrt{6}}{3},\frac{\sqrt{3}-2}{\sqrt{3}})\)和\((1,-\frac{\sqrt{6}}{3},\frac{\sqrt{3}+2}{\sqrt{3}})\),即\((1,\frac{\sqrt{6}}{3},1-\frac{2\sqrt{3}}{3})\)和\((1,-\frac{\sqrt{6}}{3},1+\frac{2\sqrt{3}}{3})\)。
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