Hi I tried to find the state space form using Matlab but my

Hi, I tried to find the state space form using Matlab but my solution is different from Matlab matrix.

This is my code for part i) http://imgur.com/QCfOqXK and code for part ii) http://imgur.com/qfW4EeJ

Could you please take a look at the code and see what I did wrong? Also, try to work out the state space question. e.g x=Ax+Bu

Thank you!

One mistake found in first part is dimension of P . It should be 2X2 in part (1). The following codes are working, check.

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Dr = [1 3 12];
Nr = 4;
[A, B, C ,D] = tf2ss(Nr,Dr)
P=[0 1 ; 1 0 ];
Ap=inv(P)*A*P
Bp=inv(P)*B
Cp=C*P
Dp=D

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Output is shown below

Ap =

0 1
-12 -3

Bp =

0
1

Cp =

4 0

Dp =

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Dr = [1 14 540 20000];
Nr = [ 20 60 40];
[A, B, C ,D] = tf2ss(Nr,Dr)
P=[0 0 1 ; 0 1 0 ; 1 0 0 ];
Ap=inv(P)*A*P
Bp=inv(P)*B
Cp=C*P
Dp=D

-----------------------------------------------------------------------------------------------------------------------------------------------------

The output is shown below

Ap =

0 1 0
0 0 1
-20000 -540 -14

Bp =

0
0
1

Cp =

40 60 20

Dp =