Boolean Algebra

 1.      Using the following declarations, determine if the following statements are true or false.
        int j = 4;  int k = 8;  int y = 9;
   (a)    j <= 9
   (b)   y <= k
   (c)    (y+1 > j)
   (d)   (y < k) && (y < j)
   (e)    (k > j) || ((j < 3) && (j > 1))
   (f)     !(k < j)
   (g)    ! ((k > 9) || (k > 1))
   (h)    ! (!(y>2) && !(k<2))
 
2.      Using the following declarations, determine if the following statements are true or false.
        int w = 0;  int h = 0;  int r = 1;
   (a)    w < 0
   (b)   h < w
   (c)    h <= w
   (d)   !(h == r)
   (e)    !(h < r)
   (f)     !((r > h) && (w <= h))
   (g)    ((r > w) && (w < 4)) || (w > -1)
   (h)    (r < 4) || ((w > h) || !(r < 3))

3. Prove the following Identities by filling in the truth tables.

(a) X || X = X

X X||X X
False    
True    

(b) X && X = X

X X&&X X
False    
True    

(c) !(X||Y) = !X && !Y

X Y !(X||Y) !X && !Y
T T    
T F    
F T    
F F    

(d) !(X&&Y) = !X || !Y

X Y !(X&&Y) !X || !Y
T T    
T F    
F T    
F F    

(e) X && (X||Y) = X

X Y X && (X||Y)
T T  
T F  
F T  
F F  

(f) X && (X||Y) = X || (X&&Y)

X Y X && (X||Y) X || (X&&Y)
T T    
T F    
F T    
F F    

(g) X && (!X || Y) = (!X && X) || (X && Y)

X Y X && (!X || Y) (!X && X) || (X && Y)
T T    
T F    
F T    
F F    

(h) (X || Y) && (X || !Y) = X || (Y && !Y)

X Y (X || Y) && (X || !Y) X || (Y && !Y)
T T    
T F    
F T    
F F