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truthtable

Not x and not y = not (x or y)?


the question

F (x,y,z) = ¬x¬y , and G(x,y,z) = ¬(x + y) is F(x,y,z) = G(x,y,z) ?

Will we get the same truth table output?

This is the truth table outputs that I got and it’s not equal but others say it equal, I’m not sure how can it be equal?

F(x,y,z) = not x and not y Both x and y need to be 0 And z is ignored.

G(x,y,z) = not (x or y) At least one of x or y need to be 0 And z is also ignored.

Am I doing something wrong here?

My truth tables


Solution

  • "not x" is true if x is false. "not y" is true if y is false. So, "not x and not y" is true only if both x and y are false.

    On the other hand, "not (x or y)" is true if the entire expression inside the parentheses (x or y) is false. This happens only when both x and y are false.

    Therefore, "not x and not y" is logically equivalent to "not (x or y)." or, ¬x∧¬y is equivalent to ¬(x∨y) in terms of boolean logic.