(6A)
(6A)
Line 5: Line 5:
 
'''Proof:'''
 
'''Proof:'''
  
<math>x(t) \to System \to y(t)=e^{x(t)} \to Time Shift(t0) \to z(t)=y(t-t0)</math>
+
<math>x(t-k) \to System \to y(t)=(k+1)^{2}x(t-k-1) \to Time Shift(t0) \to z(t)=y(t-t0)</math>
  
<math>\,                                                            =e^{x(t-t0)}\,</math>
+
<math>\,                                                            =(k+1)^{2}x(t-t0-k-1)\,</math>
  
  
  
<math>x(t) \to Time Shift(t0) \to y(t)=x(t-t0) \to System \to z(t)=e^{y(t)}</math>
+
<math>x(t-k) \to Time Shift(t0) \to y(t)=x(t-t0-k) \to System \to z(t)=(k1+1)^{2}y(t-k1-1)</math>
  
<math>\,                                                            =e^{x(t-t0)}\,</math>
+
<math>\,                                                            =(t0+k+1)^{2}x(t-t0-k-1)\,</math>
  
 
+
It is not time invariant.
Both cascades yielded the same outputs, thus <math>\,y(t)=e^{x(t)}\,</math> is time invariant.
+

Revision as of 17:27, 12 September 2008

6A

$ \,x(t-k) \to System \to y(t)=(k+1)^{2}x(t-k-1)\, $


Proof:

$ x(t-k) \to System \to y(t)=(k+1)^{2}x(t-k-1) \to Time Shift(t0) \to z(t)=y(t-t0) $

$ \, =(k+1)^{2}x(t-t0-k-1)\, $


$ x(t-k) \to Time Shift(t0) \to y(t)=x(t-t0-k) \to System \to z(t)=(k1+1)^{2}y(t-k1-1) $

$ \, =(t0+k+1)^{2}x(t-t0-k-1)\, $

It is not time invariant.

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Abstract algebra continues the conceptual developments of linear algebra, on an even grander scale.

Dr. Paul Garrett