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:~ksoong
 
:~ksoong
  
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Answer from Prof. MImi
 
*In the step where you replaced -n by k, you forgot to replace the n inside the summation. Also, the first sum should then go from -2 to -infinity, instead of infinity.
 
*In the step where you replaced -n by k, you forgot to replace the n inside the summation. Also, the first sum should then go from -2 to -infinity, instead of infinity.
 
*Actually, I do not see why you replaced -n by k in both sums. IN the first sum, you should have set k=n-2. In the second sum, you did not need to make any change of variable.
 
*Actually, I do not see why you replaced -n by k in both sums. IN the first sum, you should have set k=n-2. In the second sum, you did not need to make any change of variable.
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*The simplification of the first summation following the arrow is incorrect: you would need to add two terms instead of just one.  
 
*The simplification of the first summation following the arrow is incorrect: you would need to add two terms instead of just one.  
 
*The equality following the arrow is only valid when |z|>|a|.You must write this next to the equality!
 
*The equality following the arrow is only valid when |z|>|a|.You must write this next to the equality!
 
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*This explanation would be much clearer if you had typed in your answer: this way I could make notes directly inside the computations and cross-out and replace stuff using different colors.
Note: this explanation would be much clearer if you had typed in your answer: this way I could make notes directly inside the computations and cross-out and replace stuff using different colors.
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Anybody sees anything else? Do you have more questions?
 
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Revision as of 14:05, 11 September 2010

I'm not sure if I've done this correctly in the first place. I would like your input before I actually attempt to inverse it. Thank you. Untitled-2.jpg

Inverseatransformksoong.jpg

EDIT: I have realized at least that my ROCs have been backwards. I had understood it as trying to make the 1/z term go to zero to converge. Well, that's wrong.
~ksoong

Answer from Prof. MImi

  • In the step where you replaced -n by k, you forgot to replace the n inside the summation. Also, the first sum should then go from -2 to -infinity, instead of infinity.
  • Actually, I do not see why you replaced -n by k in both sums. IN the first sum, you should have set k=n-2. In the second sum, you did not need to make any change of variable.
  • The arrow in the middle of your computations, and the one towards the end should both be replaced by equal signs.
  • The simplification of the first summation following the arrow is incorrect: you would need to add two terms instead of just one.
  • The equality following the arrow is only valid when |z|>|a|.You must write this next to the equality!
  • This explanation would be much clearer if you had typed in your answer: this way I could make notes directly inside the computations and cross-out and replace stuff using different colors.

Anybody sees anything else? Do you have more questions?


Alumni Liaison

Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood