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26 changes: 13 additions & 13 deletions source/linear-algebra/source/02-EV/03.ptx
Original file line number Diff line number Diff line change
Expand Up @@ -40,8 +40,8 @@

<observation>
<p>
Recall that if <m>S=\left\{\vec{v}_1,\dots, \vec{v}_n\right\}</m> is subset of vectors in <m>\IR^n</m>, then <m>\vspan(S)</m> is the set of all linear combinations of vectors in <m>S</m>.
In <xref ref="EV2"/>, we learned how to decide whether <m>\vspan(S)</m> was equal to all of <m>\IR^n</m> or something strictly smaller.
Recall that if <m>S=\left\{\vec{v}_1,\dots, \vec{v}_n\right\}</m> is subset of vectors in <m>\IR^n</m>, then <m>\vspan S</m> is the set of all linear combinations of vectors in <m>S</m>.
In <xref ref="EV2"/>, we learned how to decide whether <m>\vspan S</m> was equal to all of <m>\IR^n</m> or something strictly smaller.
</p>
</observation>
<activity>
Expand All @@ -55,9 +55,9 @@
<p>
Let <m>S</m> denote a set of vectors in <m>\IR^3</m> and suppose that
<m>\left[\begin{array}{c}1\\2\\3\end{array}\right],
\left[\begin{array}{c}4\\5\\6\end{array}\right]\in\vspan(S)</m>.
\left[\begin{array}{c}4\\5\\6\end{array}\right]\in\vspan S</m>.
Which of the following vectors might
<em>not</em> belong to <m>\vspan(S)</m>?
<em>not</em> belong to <m>\vspan S</m>?
<ol marker="A." cols="2">
<li><m>\left[\begin{array}{c}0\\0\\0\end{array}\right]</m></li>
<li><m>\left[\begin{array}{c}1\\2\\3\end{array}\right]+
Expand All @@ -78,9 +78,9 @@
<statement>
<p>
More generally, let <m>S</m> denote a set of vectors in <m>\IR^n</m> and suppose that
<m>\vec v,\vec w\in\vspan(S)</m> and <m>c\in\mathbb R</m>.
<m>\vec v,\vec w\in\vspan S</m> and <m>c\in\mathbb R</m>.
Which of the following vectors
<em>must</em> belong to <m>\vspan(S)</m>?
<em>must</em> belong to <m>\vspan S</m>?
<ol marker="A." cols="2">
<li><m>\vec 0</m></li>
<li><m>\vec v+\vec w</m></li>
Expand Down Expand Up @@ -269,21 +269,21 @@

<observation>
<p>
If <m>S</m> is any set of vectors in <m>\IR^n</m>, then the set <m>\vspan(S)</m> has the following properties:
If <m>S</m> is any set of vectors in <m>\IR^n</m>, then the set <m>\vspan S</m> has the following properties:
<ul>
<li>
<p>
the set <m>\vspan(S)</m> is non-empty.
the set <m>\vspan S</m> is non-empty.
</p>
</li>
<li>
<p>
the set <m>\vspan(S)</m> is <q>closed under addition</q>: for any <m>\vec{u},\vec{v}\in \vspan(S)</m>, the sum <m>\vec{u}+\vec{v}</m> is also in <m>\vspan(S)</m>.
the set <m>\vspan S</m> is <q>closed under addition</q>: for any <m>\vec{u},\vec{v}\in \vspan S</m>, the sum <m>\vec{u}+\vec{v}</m> is also in <m>\vspan S</m>.
</p>
</li>
<li>
<p>
the set <m>\vspan(S)</m> is <q>closed under scalar multiplication</q>: for any <m>\vec{u}\in\vspan(S)</m> and scalar <m>c\in\IR</m>, the product <m>c\vec{u}</m> is also in <m>\vspan(S)</m>.
the set <m>\vspan S</m> is <q>closed under scalar multiplication</q>: for any <m>\vec{u}\in\vspan S</m> and scalar <m>c\in\IR</m>, the product <m>c\vec{u}</m> is also in <m>\vspan S</m>.
</p>
</li>
</ul>
Expand Down Expand Up @@ -1033,21 +1033,21 @@ that is, <m>(kx)+(ky)=(kx)(ky)</m>. This is verified by the following calculatio
<task>
<statement>
<p>
Given the set of ingredients <me>S=\{\textrm{flour}, \textrm{yeast}, \textrm{salt}, \textrm{water}, \textrm{sugar}, \textrm{milk}\}</me>, how should we think of the subspace <m>\vspan(S)</m>?
Given the set of ingredients <me>S=\{\textrm{flour}, \textrm{yeast}, \textrm{salt}, \textrm{water}, \textrm{sugar}, \textrm{milk}\}</me>, how should we think of the subspace <m>\vspan S</m>?
</p>
</statement>
</task>
<task>
<statement>
<p>
What is one meal that lives in the subspace <m>\vspan(S)</m>?
What is one meal that lives in the subspace <m>\vspan S</m>?
</p>
</statement>
</task>
<task>
<statement>
<p>
What is one meal that does not live in the subspace <m>\vspan(S)</m>?
What is one meal that does not live in the subspace <m>\vspan S</m>?
</p>
</statement>
</task>
Expand Down
2 changes: 1 addition & 1 deletion source/linear-algebra/source/02-EV/05.ptx
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ In this analogy, a <em>recipe</em> was defined to be a list of amounts of each i
<task>
<statement>
<p>
Does <q>pizza</q> live inside of <m>\vspan(S)</m>?
Does <q>pizza</q> live inside of <m>\vspan S</m>?
</p>
</statement>
</task>
Expand Down
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