Mathmation required!

[Katie Kicks Ass]

Ok I have got stressed out about this for too long now, does anybody know how to do complex truth tables and simplify Booloean Expressions?

I need some one to simplfy:
_ _ _

A.B+A.B+A.B

With truth table of simplfied equation.

And this truth table completing.

[FirstMove]

Excel can do all the work for you! It has AND and OR functions for prescisely this job.

e.g. =+AND(1,1)=1

I think if you simplify symbolically you just get A.B, but I suggest you check.

What is the Z column for in you spreadsheet? It looks like NOT ( A . B)

[David Franklin]

Originally Posted by Katie Kicks Ass

Ok I have got stressed out about this for too long now, does anybody know how to do complex truth tables and simplify Booloean Expressions?

I need some one to simplfy:
_ _ _

A.B+A.B+A.B

As it stands, I can't work out what you're asking here (I'm assuming the _ are supposed to be overbars denoting complement, but the alignment has gone hopelessly wrong). Do you want to try again? I suggest you use ' to denote complement (e.g. A'.B = (NOT A) AND B) as you will have far fewer problems with the vBulletin software mucking up the formatting.

As far as the spreadsheet goes - what is the problem you are having? Can you really not work out what "not B" is given B?

[Katie Kicks Ass]

No i can't i could do with someone just telling me the answer i've stressed too long over it and i cant understand it for toffee.

BTW its (NOT A).(NOT B)+A.(NOT B)+A.B

[David Franklin]

Originally Posted by Katie Kicks Ass

No i can't i could do with someone just telling me the answer i've stressed too long over it and i cant understand it for toffee.

BTW its (NOT A).(NOT B)+A.(NOT B)+A.B

(NOT A).(NOT B)+A.(NOT B)+A.B = NOT ((NOT A).B)

For the spreadsheet, If B = 0, then NOT B = 1. If B=1 then NOT B = 0.

Once you've filled in the "NOT B" column, then A. (NOT B) = 1 if "A = 1 and (NOT B) = 1", otherwise it = 0.

[FirstMove]

<snip>

[bigdjiver]

Originally Posted by David Franklin

(NOT A).(NOT B)+A.(NOT B)+A.B = NOT ((NOT A).B)

For the spreadsheet, If B = 0, then NOT B = 1. If B=1 then NOT B = 0.

Once you've filled in the "NOT B" column, then A. (NOT B) = 1 if "A = 1 and (NOT B) = 1", otherwise it = 0.

My boolean logic is very rusty. I seek enlightenment.

I thought the + sign meant OR and the . meant AND

I simplified (NOT A).(NOT B)+A.(NOT B)
to (NOT A OR A).(NOT B)
then to (NOT B)

Then I simplified (NOT B) OR A.B
to (NOT B) OR A

Do I remember wrong?

[David Franklin]

Originally Posted by bigdjiver

My boolean logic is very rusty. I seek enlightenment.

I thought the + sign meant OR and the . meant AND

I simplified (NOT A).(NOT B)+A.(NOT B)
to (NOT A OR A).(NOT B)
then to (NOT B)

Then I simplified (NOT B) OR A.B
to (NOT B) OR A

They're both correct, yours is probably a bit simpler to be honest. (I just went for the "the only way this can be false is if A=0 and B=1" approach).

[bigdjiver]

Originally Posted by David Franklin

They're both correct, yours is probably a bit simpler to be honest. (I just went for the "the only way this can be false is if A=0 and B=1" approach).

Thanks.

[Beowulf]

I'm just back from London and my brain is fried.

I got as far as realising that (2B)+(NOT 2B) was not the question

bigdjiver and David Franklin got it right before me though.. so to them