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== Example of a Non-Linear System ==
 
== Example of a Non-Linear System ==
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<font size="3">Equation - <math>y[n] = x[n]^2</math></font>
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  <math>x_{1}[n] \to sys \to *a \to</math>
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                      <math>+ \to a x_{1}[n]^2 + b x_{2}[n]^2</math>
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  <math>x_{2}[n] \to sys \to *b \to</math>
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  <math>x_{1}[n] \to *a \to</math>
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                <math>+ \to sys \to (a x_{1}[n] + b x_{2}[n])^2</math>
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  <math>x_{2}[n] \to *b \to</math>
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<font size="3">Since <math>a x_{1}[n]^2 + b x_{2}[n]^2</math> and <math>(a x_{1}[n] + b x_{2}[n])^2</math> are not equal, the system is not linear.</font>

Revision as of 12:16, 10 September 2008

Definition

If

 $ x_{1}(t) \to sys \to *a \to $
                      $ + \to a x_{1}(t) + b x_{2}(t) $
 $ x_{2}(t) \to sys \to *b \to $

And

 $ x_{1}(t) \to *a \to $
               $ + \to sys \to a x_{1}(t) + b x_{2}(t) $
 $ x_{2}(t) \to *b \to $

And $ a $ and $ b $ are any complex number,

Then the system is linear.


Example of a Linear System

Example of a Non-Linear System

Equation - $ y[n] = x[n]^2 $

 $ x_{1}[n] \to sys \to *a \to $
                      $ + \to a x_{1}[n]^2 + b x_{2}[n]^2 $
 $ x_{2}[n] \to sys \to *b \to $
 $ x_{1}[n] \to *a \to $
               $ + \to sys \to (a x_{1}[n] + b x_{2}[n])^2 $
 $ x_{2}[n] \to *b \to $

Since $ a x_{1}[n]^2 + b x_{2}[n]^2 $ and $ (a x_{1}[n] + b x_{2}[n])^2 $ are not equal, the system is not linear.

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett