How do I get Z' + X'Y' + XY from Z' + ZX'Y' + ZXY?












1












$begingroup$


So I'm trying to simplify an equation using boolean algebra. I'm still very confused as to how all the rules work and such, but I feel like I'm very close to the answer.



The original equation is (in canonical SOP form):



Z'X'Y' + Z'X'Y + Z'XY' + Z'XY + ZX'Y' + ZXY



So far I've gotten this far:



Distributive Rule 12a: Z'X'(Y + Y') + Z'X(Y' + Y) + ZX'Y' + ZXY



Identity Rule 6a: Z'X' + Z'X + ZX'Y' + ZXY



Rule 12a again: Z'(X' + X) + ZX'Y' + ZXY



Rule 6a again: Z' + ZX'Y' + ZXY



My issue is that the answer is Z' + X'Y' + XY, but how do I get there? Because doesn't ZX'Y' + ZXY simplify to Z(X'Y' + XY) = Z?



What am I doing wrong? Are the steps I have so far correct?



Thanks.










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  • $begingroup$
    Isn't it supposed to be in capitals in the title?
    $endgroup$
    – Mohammad Zuhair Khan
    Jan 31 at 5:16










  • $begingroup$
    @MohammadZuhairKhan fixed.
    $endgroup$
    – ESM
    Jan 31 at 5:20
















1












$begingroup$


So I'm trying to simplify an equation using boolean algebra. I'm still very confused as to how all the rules work and such, but I feel like I'm very close to the answer.



The original equation is (in canonical SOP form):



Z'X'Y' + Z'X'Y + Z'XY' + Z'XY + ZX'Y' + ZXY



So far I've gotten this far:



Distributive Rule 12a: Z'X'(Y + Y') + Z'X(Y' + Y) + ZX'Y' + ZXY



Identity Rule 6a: Z'X' + Z'X + ZX'Y' + ZXY



Rule 12a again: Z'(X' + X) + ZX'Y' + ZXY



Rule 6a again: Z' + ZX'Y' + ZXY



My issue is that the answer is Z' + X'Y' + XY, but how do I get there? Because doesn't ZX'Y' + ZXY simplify to Z(X'Y' + XY) = Z?



What am I doing wrong? Are the steps I have so far correct?



Thanks.










share|cite|improve this question











$endgroup$












  • $begingroup$
    Isn't it supposed to be in capitals in the title?
    $endgroup$
    – Mohammad Zuhair Khan
    Jan 31 at 5:16










  • $begingroup$
    @MohammadZuhairKhan fixed.
    $endgroup$
    – ESM
    Jan 31 at 5:20














1












1








1





$begingroup$


So I'm trying to simplify an equation using boolean algebra. I'm still very confused as to how all the rules work and such, but I feel like I'm very close to the answer.



The original equation is (in canonical SOP form):



Z'X'Y' + Z'X'Y + Z'XY' + Z'XY + ZX'Y' + ZXY



So far I've gotten this far:



Distributive Rule 12a: Z'X'(Y + Y') + Z'X(Y' + Y) + ZX'Y' + ZXY



Identity Rule 6a: Z'X' + Z'X + ZX'Y' + ZXY



Rule 12a again: Z'(X' + X) + ZX'Y' + ZXY



Rule 6a again: Z' + ZX'Y' + ZXY



My issue is that the answer is Z' + X'Y' + XY, but how do I get there? Because doesn't ZX'Y' + ZXY simplify to Z(X'Y' + XY) = Z?



What am I doing wrong? Are the steps I have so far correct?



Thanks.










share|cite|improve this question











$endgroup$




So I'm trying to simplify an equation using boolean algebra. I'm still very confused as to how all the rules work and such, but I feel like I'm very close to the answer.



The original equation is (in canonical SOP form):



Z'X'Y' + Z'X'Y + Z'XY' + Z'XY + ZX'Y' + ZXY



So far I've gotten this far:



Distributive Rule 12a: Z'X'(Y + Y') + Z'X(Y' + Y) + ZX'Y' + ZXY



Identity Rule 6a: Z'X' + Z'X + ZX'Y' + ZXY



Rule 12a again: Z'(X' + X) + ZX'Y' + ZXY



Rule 6a again: Z' + ZX'Y' + ZXY



My issue is that the answer is Z' + X'Y' + XY, but how do I get there? Because doesn't ZX'Y' + ZXY simplify to Z(X'Y' + XY) = Z?



What am I doing wrong? Are the steps I have so far correct?



Thanks.







boolean-algebra






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share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 31 at 5:20







ESM

















asked Jan 31 at 5:13









ESMESM

104




104












  • $begingroup$
    Isn't it supposed to be in capitals in the title?
    $endgroup$
    – Mohammad Zuhair Khan
    Jan 31 at 5:16










  • $begingroup$
    @MohammadZuhairKhan fixed.
    $endgroup$
    – ESM
    Jan 31 at 5:20


















  • $begingroup$
    Isn't it supposed to be in capitals in the title?
    $endgroup$
    – Mohammad Zuhair Khan
    Jan 31 at 5:16










  • $begingroup$
    @MohammadZuhairKhan fixed.
    $endgroup$
    – ESM
    Jan 31 at 5:20
















$begingroup$
Isn't it supposed to be in capitals in the title?
$endgroup$
– Mohammad Zuhair Khan
Jan 31 at 5:16




$begingroup$
Isn't it supposed to be in capitals in the title?
$endgroup$
– Mohammad Zuhair Khan
Jan 31 at 5:16












$begingroup$
@MohammadZuhairKhan fixed.
$endgroup$
– ESM
Jan 31 at 5:20




$begingroup$
@MohammadZuhairKhan fixed.
$endgroup$
– ESM
Jan 31 at 5:20










2 Answers
2






active

oldest

votes


















0












$begingroup$


Because doesn't $ZX'Y'+ZXY$ simplify to $Z(X'Y'+XY)=Z$?




No, because $(XY)'ne X'Y'$, so in parentheses you do NOT have something of the form "$A+A'$". (In fact, by De Morgan's laws, $(XY)'=X'+Y'$.)




My issue is that the answer is $Z'+X'Y'+XY$, but how do I get there?




There are some additional useful properties that often help simplify boolean expressions. Here are two of them.



1) $color{red}{A+AB=A}$. Proof:
$$A+AB=A1+AB=A(1+B)=A1=A.$$



2) $color{red}{A+A'B=A+B}$. Proof:
$$A+A'B=A+AB+A'B=A+(A+A')B=A+1B=A+B.$$



Now, $Z'+ZX'Y'+ZXY=Z'+Z(X'Y'+XY)=Z'+X'Y'+XY$, where the last step is an application of the second property above (with $A=Z'$ and $B=X'Y'+XY$).






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
    $endgroup$
    – ESM
    Jan 31 at 5:55



















0












$begingroup$

You need to immediately add the following equivalence to your toolbox:



Reduction



$P + P'Q=P+Q$



That is, the $P$ term 'reduces' the $P'Q$ term to just $Q$



With that, you can see how in your expression, the $Z'$ term reduces the $ZX'Y'$ to $X'Y'$, and also reduces the $ZXY$ to $XY$. So there:



$Z'+ZX'Y'+ZXY overset{Reduction x 2}{=} Z'+X'Y'+XY$






share|cite|improve this answer









$endgroup$














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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    0












    $begingroup$


    Because doesn't $ZX'Y'+ZXY$ simplify to $Z(X'Y'+XY)=Z$?




    No, because $(XY)'ne X'Y'$, so in parentheses you do NOT have something of the form "$A+A'$". (In fact, by De Morgan's laws, $(XY)'=X'+Y'$.)




    My issue is that the answer is $Z'+X'Y'+XY$, but how do I get there?




    There are some additional useful properties that often help simplify boolean expressions. Here are two of them.



    1) $color{red}{A+AB=A}$. Proof:
    $$A+AB=A1+AB=A(1+B)=A1=A.$$



    2) $color{red}{A+A'B=A+B}$. Proof:
    $$A+A'B=A+AB+A'B=A+(A+A')B=A+1B=A+B.$$



    Now, $Z'+ZX'Y'+ZXY=Z'+Z(X'Y'+XY)=Z'+X'Y'+XY$, where the last step is an application of the second property above (with $A=Z'$ and $B=X'Y'+XY$).






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
      $endgroup$
      – ESM
      Jan 31 at 5:55
















    0












    $begingroup$


    Because doesn't $ZX'Y'+ZXY$ simplify to $Z(X'Y'+XY)=Z$?




    No, because $(XY)'ne X'Y'$, so in parentheses you do NOT have something of the form "$A+A'$". (In fact, by De Morgan's laws, $(XY)'=X'+Y'$.)




    My issue is that the answer is $Z'+X'Y'+XY$, but how do I get there?




    There are some additional useful properties that often help simplify boolean expressions. Here are two of them.



    1) $color{red}{A+AB=A}$. Proof:
    $$A+AB=A1+AB=A(1+B)=A1=A.$$



    2) $color{red}{A+A'B=A+B}$. Proof:
    $$A+A'B=A+AB+A'B=A+(A+A')B=A+1B=A+B.$$



    Now, $Z'+ZX'Y'+ZXY=Z'+Z(X'Y'+XY)=Z'+X'Y'+XY$, where the last step is an application of the second property above (with $A=Z'$ and $B=X'Y'+XY$).






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
      $endgroup$
      – ESM
      Jan 31 at 5:55














    0












    0








    0





    $begingroup$


    Because doesn't $ZX'Y'+ZXY$ simplify to $Z(X'Y'+XY)=Z$?




    No, because $(XY)'ne X'Y'$, so in parentheses you do NOT have something of the form "$A+A'$". (In fact, by De Morgan's laws, $(XY)'=X'+Y'$.)




    My issue is that the answer is $Z'+X'Y'+XY$, but how do I get there?




    There are some additional useful properties that often help simplify boolean expressions. Here are two of them.



    1) $color{red}{A+AB=A}$. Proof:
    $$A+AB=A1+AB=A(1+B)=A1=A.$$



    2) $color{red}{A+A'B=A+B}$. Proof:
    $$A+A'B=A+AB+A'B=A+(A+A')B=A+1B=A+B.$$



    Now, $Z'+ZX'Y'+ZXY=Z'+Z(X'Y'+XY)=Z'+X'Y'+XY$, where the last step is an application of the second property above (with $A=Z'$ and $B=X'Y'+XY$).






    share|cite|improve this answer











    $endgroup$




    Because doesn't $ZX'Y'+ZXY$ simplify to $Z(X'Y'+XY)=Z$?




    No, because $(XY)'ne X'Y'$, so in parentheses you do NOT have something of the form "$A+A'$". (In fact, by De Morgan's laws, $(XY)'=X'+Y'$.)




    My issue is that the answer is $Z'+X'Y'+XY$, but how do I get there?




    There are some additional useful properties that often help simplify boolean expressions. Here are two of them.



    1) $color{red}{A+AB=A}$. Proof:
    $$A+AB=A1+AB=A(1+B)=A1=A.$$



    2) $color{red}{A+A'B=A+B}$. Proof:
    $$A+A'B=A+AB+A'B=A+(A+A')B=A+1B=A+B.$$



    Now, $Z'+ZX'Y'+ZXY=Z'+Z(X'Y'+XY)=Z'+X'Y'+XY$, where the last step is an application of the second property above (with $A=Z'$ and $B=X'Y'+XY$).







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Jan 31 at 5:49

























    answered Jan 31 at 5:44









    zipirovichzipirovich

    11.3k11731




    11.3k11731












    • $begingroup$
      Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
      $endgroup$
      – ESM
      Jan 31 at 5:55


















    • $begingroup$
      Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
      $endgroup$
      – ESM
      Jan 31 at 5:55
















    $begingroup$
    Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
    $endgroup$
    – ESM
    Jan 31 at 5:55




    $begingroup$
    Ohhh I gotcha. Yea that must be using DeMorgan's Theorem then. I never thought to have the Z' and Z = A and the XY = B. Thank you so much man! That definitely helps to clear things up for me :)
    $endgroup$
    – ESM
    Jan 31 at 5:55











    0












    $begingroup$

    You need to immediately add the following equivalence to your toolbox:



    Reduction



    $P + P'Q=P+Q$



    That is, the $P$ term 'reduces' the $P'Q$ term to just $Q$



    With that, you can see how in your expression, the $Z'$ term reduces the $ZX'Y'$ to $X'Y'$, and also reduces the $ZXY$ to $XY$. So there:



    $Z'+ZX'Y'+ZXY overset{Reduction x 2}{=} Z'+X'Y'+XY$






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      You need to immediately add the following equivalence to your toolbox:



      Reduction



      $P + P'Q=P+Q$



      That is, the $P$ term 'reduces' the $P'Q$ term to just $Q$



      With that, you can see how in your expression, the $Z'$ term reduces the $ZX'Y'$ to $X'Y'$, and also reduces the $ZXY$ to $XY$. So there:



      $Z'+ZX'Y'+ZXY overset{Reduction x 2}{=} Z'+X'Y'+XY$






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        You need to immediately add the following equivalence to your toolbox:



        Reduction



        $P + P'Q=P+Q$



        That is, the $P$ term 'reduces' the $P'Q$ term to just $Q$



        With that, you can see how in your expression, the $Z'$ term reduces the $ZX'Y'$ to $X'Y'$, and also reduces the $ZXY$ to $XY$. So there:



        $Z'+ZX'Y'+ZXY overset{Reduction x 2}{=} Z'+X'Y'+XY$






        share|cite|improve this answer









        $endgroup$



        You need to immediately add the following equivalence to your toolbox:



        Reduction



        $P + P'Q=P+Q$



        That is, the $P$ term 'reduces' the $P'Q$ term to just $Q$



        With that, you can see how in your expression, the $Z'$ term reduces the $ZX'Y'$ to $X'Y'$, and also reduces the $ZXY$ to $XY$. So there:



        $Z'+ZX'Y'+ZXY overset{Reduction x 2}{=} Z'+X'Y'+XY$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Feb 1 at 3:24









        Bram28Bram28

        64.2k44793




        64.2k44793






























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