Boolean Algebra Help

Thread Starter

chengie.teo

Joined Feb 15, 2011
3
Hi,


Can anybody guide me on how to simplified the expression
1) (A'.B.C.D.E.F'.G.H) + (A+B+C+D+E+F'+G+H)
and
2) (A'.B.C.D.E.F'.G.H) . (A+B+C+D+E+F'+G+H)
 

haykp

Joined Oct 7, 2010
18
This is the solution:
1) (A'.B.C.D.E.F'.G.H) + (A+B+C+D+E+F'+G+H)
(A'.B.C.D.E.F'.G.H) = A + (B.C.D.E.F'.G.H)' = A + B' +(C.D.E.F'.G.H)'
putting this in up equation gives:
A + B' +(C.D.E.F'.G.H)' + (A+B+C+D+E+F'+G+H) = A + A +B' +B + (C.D.E.F'.G.H)' + C+D+E+F'+G+H = A + 1 + (C.D.E.F'.G.H)' + C+D+E+F'+G+H = 1
 

bitrex

Joined Dec 13, 2009
79
This is the solution:
1) (A'.B.C.D.E.F'.G.H) + (A+B+C+D+E+F'+G+H)
(A'.B.C.D.E.F'.G.H) = A + (B.C.D.E.F'.G.H)' = A + B' +(C.D.E.F'.G.H)'
putting this in up equation gives:
A + B' +(C.D.E.F'.G.H)' + (A+B+C+D+E+F'+G+H) = A + A +B' +B + (C.D.E.F'.G.H)' + C+D+E+F'+G+H = A + 1 + (C.D.E.F'.G.H)' + C+D+E+F'+G+H = 1
How did you get (A'.B.C.D.E.F'.G.H) = A + (B.C.D.E.F'.G.H)'? Wouldn't it need to be (A'.B.C.D.E.F'.G.H)' = A + (B.C.D.E.F'.G.H)'?
 

Thread Starter

chengie.teo

Joined Feb 15, 2011
3
Ya. That is the confusing part. In another post you show me that
A.B not= (A'+B') but from this post you seems to be complementing the expression and work on it.
 

Georacer

Joined Nov 25, 2009
5,182
I, too, believe that haykp is wrong.

I will use the identities (a*b*...*z)+w=(a+w)*(b+w)*...*(z+w)
and w*(a+b+...+z)=w*a+w*b+...+w*z

That said, we have:
(A'.B.C.D.E.F'.G.H) + (A+B+C+D+E+F'+G+H)=
(A'+A+B+C+D+E+F'+G+H)*(B+A+B+C+D+E+F'+G+H)*...*(H+A+B+C+D+E+F'+G+H)=
1*(B+C+D+E+F'+G+H)

and

(A'.B.C.D.E.F'.G.H) . (A+B+C+D+E+F'+G+H)=
A.A'.B.C.D.E.F'.G.H+B.A'.B.C.D.E.F'.G.H+...+H.A'.B.C.D.E.F'.G.H=
0+A'.B.C.D.E.F'.G.H

If someone thinks different, please correct me.
 

haykp

Joined Oct 7, 2010
18
Ooopsss....
My fault, yes I agree the I wrote a wrong expression in my answer. Please sorry folks.

I liked Georacer answer, very nice solution!!

Just one thing in his answer, my belief that in the final result of the first expression the "A" variable should be included also i.e.

(A'.B.C.D.E.F'.G.H) + (A+B+C+D+E+F'+G+H)=1*(A+B+C+D+E+F'+G+H)

Please correct me if I wrong.
 
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