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Question: 18. Choose a set \(S\) of four points in \({\mathbb{R}^3}\) such that aff \(S\) is the plane \(2{x_1} + {x_2} - 3{x_3} = 12\). Justify your work.

Short Answer

Expert verified

The set is \(S = \left\{ {\left( \begin{array}{l}2\\0\\0\end{array} \right),\left( \begin{array}{l}\,\,1\\12\\\,\,0\end{array} \right),\left( \begin{array}{l}\,\,0\\\,\,0\\ - 4\end{array} \right),\left( \begin{array}{l}\,\,4\\\,\,3\\ - 1\end{array} \right)} \right\}\).

Step by step solution

01

Describe the given statement

The set of four vectors that lie along the plane \(2{x_1} + {x_2} - 3{x_3} = 12\) cannot be collinear.

The set of vectors that is not collinear cannot have a line as their affine hull.

02

 Draw a conclusion

One of the possible sets of three vectors discussed above is \(S = \left\{ {\left( \begin{array}{l}2\\0\\0\end{array} \right),\left( \begin{array}{l}\,\,1\\12\\\,\,0\end{array} \right),\left( \begin{array}{l}\,\,0\\\,\,0\\ - 4\end{array} \right),\left( \begin{array}{l}\,\,4\\\,\,3\\ - 1\end{array} \right)} \right\}\).

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Most popular questions from this chapter

Suppose \({\bf{y}}\) is orthogonal to \({\bf{u}}\) and \({\bf{v}}\). Show that \({\bf{y}}\) is orthogonal to every \({\bf{w}}\) in Span \(\left\{ {{\bf{u}},\,{\bf{v}}} \right\}\). (Hint: An arbitrary \({\bf{w}}\) in Span \(\left\{ {{\bf{u}},\,{\bf{v}}} \right\}\) has the form \({\bf{w}} = {c_1}{\bf{u}} + {c_2}{\bf{v}}\). Show that \({\bf{y}}\) is orthogonal to such a vector \({\bf{w}}\).)

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