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Student Support Forum: 'Solving for a variable' topicStudent Support Forum > General > "Solving for a variable"

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Author Comment/Response
Gerhard Schoenthal
10/30/00 05:45am



If I have the following notebook why do I get {{ }} as an
answer at the bottom and how should I fix my problem?

Gerhard

In[1]:=
\!\(Cx = \(\[Epsilon]x*\[Epsilon]o*A\)\/xx\)

Out[1]=
\!\(\(A\ \[Epsilon]o\ \[Epsilon]x\)\/xx\)

In[2]:=
\!\(Cs = \(\[Epsilon]s*\[Epsilon]o*A\)\/xs\)

Out[2]=
\!\(\(A\ \[Epsilon]o\ \[Epsilon]s\)\/xs\)

In[29]:=
\!\(Cm = \(\[Epsilon]m*\[Epsilon]o*A\)\/xm\)

Out[29]=
\!\(\(A\ \[Epsilon]g\ \[Epsilon]o\)\/xm\)

In[10]:=
\[Epsilon]m=\[Epsilon]s=\[Epsilon]g

Out[10]=
\[Epsilon]g

In[5]:=
Sx=1/Cx

Out[5]=
\!\(xx\/\(A\ \[Epsilon]o\ \[Epsilon]x\)\)

In[14]:=
Ss=1/Cs

Out[14]=
\!\(xs\/\(A\ \[Epsilon]g\ \[Epsilon]o\)\)

In[30]:=
Sm=1/Cm

Out[30]=
\!\(xm\/\(A\ \[Epsilon]g\ \[Epsilon]o\)\)

In[18]:=
Smax=2*(Sx+Ss)

Out[18]=
\!\(2\ \((
xs\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
xx\/\(A\ \[Epsilon]o\ \[Epsilon]x\))\)\)

In[31]:=
Smin=Smax+Sm

Out[31]=
\!\(xm\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
2\ \((xs\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
xx\/\(A\ \[Epsilon]o\ \[Epsilon]x\))\)\)

In[32]:=
Cr=Smin/Smax

Out[32]=
\!\(\(xm\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
2\ \((xs\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
xx\/\(A\ \[Epsilon]o\ \[Epsilon]x\))\)\)\/\(2\
\((xs\/\(A\ \[Epsilon]g\ \[Epsilon]o\) +
xx\/\(A\ \[Epsilon]o\ \[Epsilon]x\))\)\)\)

In[35]:=
Simplify[Out[32]]

Out[35]=
\!\(\(2\ xx\ \[Epsilon]g + xm\ \[Epsilon]x +
2\ xs\ \[Epsilon]x\)\/\(2\ xx\ \[Epsilon]g + 2\ xs\
\[Epsilon]x\)\)

In[38]:=
Solve[Cr==Out[35],xm]

Out[38]=
{{}}


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Subject (listing for 'Solving for a variable')
Author Date Posted
Solving for a variable Gerhard Scho... 10/30/00 05:45am
Re: Solving for a variable Forum Modera... 10/30/00 06:00am
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