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February 3rd, 2014, 10:45 AM   #1
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Given truth table with 3 variables, find boolean expression

I don't know if I'm doing this right, but first I try to find the rule that most closely resembles the given problem. It's either XOR or XNOR. I chose XOR and created a blank
truth table and tried to add combinations to XOR that would allow me to get rid of that one extra 1 (from XOR) and change the appropriate 1s to 0s and 0s to 1s. Nothing I've tried helps me solve this problem. I've tried (A?B?C).A' ; (A?B?C).(A.B') ; (A?B?C).(A'?C') ; and quite a few others. For this type of problem, are we supposed to just guess different combinations and just hope it all works out? Any help would be appreciated. Thanks!
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February 3rd, 2014, 12:50 PM   #2
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Re: Given truth table with 3 variables, find boolean express

Just do it line by line. The last line has all three of A, B, and C being true, so it is A & B & C. The second-to-last line has C false, so it's A & B & -C. The combined expression so far is (A & B & C) | (A & B & -C). Just keep adding lines until you're done. (Of course you can go top to bottom as well.) Here I'm using & for AND, | for OR, and - for NOT; substitute whatever symbols your class uses.
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February 3rd, 2014, 03:22 PM   #3
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Re: Given truth table with 3 variables, find boolean express

Hello, unwisetome3!


[color=beige]. . [/color]

The statement is false in rows 2, 5, 6.

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