F(X,Y) = (X'+Y) . (X+Y) . (X'+X)
Answers
Theorem 1: Let (B,+, . , ‘, 0,1) be a Boolean Algebra. Then the following hold:
a) x+x=x and x.x=x for all x in B
b) x+1=1 and 0.x=0 for all x in B
c) x+(xy)=x and x.(x+y)=x for all x and y in B
Proof:
a) x = x+0 Identity laws
= x+xx’ Complementation laws
= (x+x).(x+x’) because + is distributive over .
= (x+x).1 Complementation laws
= x+x Identity laws
x = x.1 Identity laws
= x.(x+x’) Complementation laws
= x.x +x.x’ because + is distributive over .
= x.x+0 Identity laws
= x.x
b) x+1 =x+(x+x’) Complementation laws
= (x+x)+x’ + is associative
= x+x’ using (a)
= 1 Complementation laws
0.x =(x’.x).x Complementation laws
= x’.(x.x) . is associative
= x’.x using (a)
=0 Complementation laws
c) x+(xy) = x.1+x.y Identity laws
=x.(1+y) because + is distributive over .