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Melody

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यूजर का नामMelody
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Melody  11 Feb 2022
 #2
avatar+118733 
0

Nice work 4X  

11 Nov 2014
 #3
avatar+118733 
0

this is going to be a major effort has I have to revise matrices from the beginning LOL

Talk about making life difficult fo myself.

I viewed this you tube clip before I started.

http://www.youtube.com/watch?v=pKZyszzmyeQ

 

 

$$\begin{pmatrix}
3&2&1 \\
-1&1&-2 \\
5&2&10 \\
\end{pmatrix} &
\begin{pmatrix}
x\\
y\\
z
\end{pmatrix}&=&
\begin{pmatrix}
1\\
0\\
39
\end{pmatrix}$$

 

Now  det=3(14)-2(0)+1(-7)=42-7=35

 

$$\dfrac{1}{35}&
\begin{pmatrix}
14&-18&-5 \\
0& 25&5\\
-7&4&5
\end{pmatrix} &
\begin{pmatrix}
3&2&1 \\
-1&1&-2 \\
5&2&10 \\
\end{pmatrix} &
\begin{pmatrix}
x& \\
y& \\
z&
\end{pmatrix} &=&
\dfrac{1}{35}&
\begin{pmatrix}
14&-18&-5 \\
0& 25&5\\
-7&4&5
\end{pmatrix} &
\begin{pmatrix}
1& \\
0& \\
39&
\end{pmatrix}$$

 

$$\dfrac{1}{35}&
\begin{pmatrix}
35&0&0 \\
0& 35&0\\
0&0&35
\end{pmatrix} &
\begin{pmatrix}
x& \\
y& \\
z&
\end{pmatrix} &=&
\dfrac{1}{35}&
\end{pmatrix}
\begin{pmatrix}
14-0-195& \\
0+0+195& \\
-7+0+195&
\end{pmatrix}$$

 

$$\begin{pmatrix}
x& \\
y& \\
z&
\end{pmatrix} &=&
\dfrac{1}{35}&
\begin{pmatrix}
-181& \\
195& \\
188&
\end{pmatrix}$$

 

$$\begin{pmatrix}
x& \\
y& \\
z&
\end{pmatrix} &=&
\dfrac{1}{35}&
\begin{pmatrix}
-181& \\
195& \\
188&
\end{pmatrix}$$

 

the reason tha my answser and Gino's answers are different is because he assumed that =z in the middle equation was a mistype and he changed the z to a 2.

I left it as a z.

Gino's assumuption was obviously correct since his way the number worked out nicely and my way the numbers are horrible.  Even so, I have answered the question that was asked.  

 

11 Nov 2014