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(a + b*)* =

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by DanaJ » Sun Mar 01, 2009 10:11 am
You missed smth over here:
(a + b*)* =

Correct the problem and we'll try to help.
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by deepoe » Sun Mar 01, 2009 10:19 am
this is a question at the defined functions :D
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by DanaJ » Sun Mar 01, 2009 10:23 am
I'm sorry, I'm not familiar with it... I'm not from the US and you guys might have slightly different notations... If you would be so kind as to explain, maybe I could help...
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by truplayer256 » Sun Mar 01, 2009 10:34 am
Is there another piece of important information that goes along with this problem? If not, then I don't think this problem is solvable.
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by deepoe » Sun Mar 01, 2009 11:39 am
I found the answer in the book, but don't understand it really :$

(a + b*)* = (a + [2 – b])* = (a + 2 – b)* = 2 – (a + 2 – b) = 2 – a – 2 + b = –a + b = b – a. The answer is
(A).
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by DanaJ » Sun Mar 01, 2009 11:46 am
The problem might be wrong, but with the info that you provided I believe that the "*" operation is defined as:
x* = 2 - x.
After defining the problem, they ask you to calculate (a + b*)*. You begin by working the stuff in the parenthesis: b* = 2 - b and you replace b* in the initial form:
(a + b*)* = (a + 2 - b)*.
Now, from this point you consider a + 2 - b as a number on its own and you apply the operation:
(a + 2 - b)* = 2 - (a + 2 - b) = 2 - a - 2 + b = b - a.
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by welcome » Mon Mar 02, 2009 1:27 am
Deepoe, please check the question again. How come one put b=2-b fomr nowhere... there should a defined function as DanaJ said.
Shubham.
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