
Computer Science Computer Science Forum 
 LinkBack  Thread Tools  Display Modes 
March 9th, 2017, 12:09 PM  #1 
Member Joined: Jan 2014 Posts: 42 Thanks: 0  boolean Algebra Problems
Why does A'B' cancel out in this problem: A'B'CD+A+B To get: CD+A+B (image boolean algebra.jpg) and can some one check to see if this is correct (refer to imageboolAlg.jpg) Thanks 
March 9th, 2017, 12:21 PM  #2 
Senior Member Joined: Sep 2015 From: Southern California, USA Posts: 1,488 Thanks: 749 
$\bar{A}\bar{B}CD + A + B = (A+B)CD+A+B ~~~~ \text{(DeMorgan's Law)}$ $(A+B)CD+(A+B) = (A+B)(CD+U) = (A+B)(U) = A+B$ 
March 9th, 2017, 04:49 PM  #3 
Member Joined: Jan 2016 From: Athens, OH Posts: 51 Thanks: 27 
I think Romsek must have misread your question. For any X and A, $$\bar{A}X+A=(\bar{A}+A)(X+A)=1(X+A)=X+A$$ Here I used that + distributes over product. Use the above twice to get your result. 

Tags 
algebra, boolean, problems 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Boolean algebra simplification using boolean rules  JustForFun2000  Computer Science  2  September 26th, 2016 09:11 AM 
Boolean algebra  unistu  Algebra  4  March 27th, 2016 09:54 PM 
Boolean Algebra  Shamieh  Calculus  2  September 12th, 2013 10:38 AM 
Boolean algebra  Anamaria  Applied Math  1  February 18th, 2011 11:16 AM 
Boolean Algebra  MoZ  Applied Math  8  January 28th, 2009 05:29 PM 