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<math>e^{(2jt)} = cos{(2t)} + jsin{(2t)} --> system --> t*{(cos{(2t)} - jsin{(2t)})}\,</math><br>
 
<math>e^{(2jt)} = cos{(2t)} + jsin{(2t)} --> system --> t*{(cos{(2t)} - jsin{(2t)})}\,</math><br>
 
<math>e^{(-2jt)} = cos{(2t)} - jsin{(2t)} --> system --> t*{(cos{(2t)} + jsin{(2t)})}\,</math><br>
 
<math>e^{(-2jt)} = cos{(2t)} - jsin{(2t)} --> system --> t*{(cos{(2t)} + jsin{(2t)})}\,</math><br>
 +
 +
Now, suppose a and b are 1/2.<br>
 +
<math>\frac{1}{2}e^{(2jt)} + frac{1}{2}e^{(-2jt)} = frac{1}{2}(cos{(2t)} + jsin{(2t)}) + frac{1}{2}cos{(2t)} - jsin{(2t)} = cos{(2t)}</math>

Revision as of 10:59, 13 September 2008

  • I am going to use the definition of Linearity that I learned in class.
  • The definition
 if x1(t) --> system --> y1(t)
x2(t) --> system --> y2(t)
Then ax1(t) + bx2(t) --> system --> ay1(t) + by2(t) , for any complex constants a,b

$ e^{(2jt)} = cos{(2t)} + jsin{(2t)} --> system --> t*{(cos{(2t)} - jsin{(2t)})}\, $
$ e^{(-2jt)} = cos{(2t)} - jsin{(2t)} --> system --> t*{(cos{(2t)} + jsin{(2t)})}\, $

Now, suppose a and b are 1/2.
$ \frac{1}{2}e^{(2jt)} + frac{1}{2}e^{(-2jt)} = frac{1}{2}(cos{(2t)} + jsin{(2t)}) + frac{1}{2}cos{(2t)} - jsin{(2t)} = cos{(2t)} $

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