Hi My teacher is a m*ron he won't (or can't) explain following: I have to find the complement of AB. The B have a bar over (inverted but I dunno how to do it in the forum) Can somebody explain to me how this is going on? Tommy
Just use an apostrophe ' character after the term instead of the bar to show the complement - like, AB' which reads "A and not B" So - DeMorgan says: not (x and y) = (not x) or (not y) not (x or y) = (not x) and (not y) Or, using the ' symbol for NOT and the usual AND and OR symbol conventions, DeMorgan is written: (xy)' = x' + y' (x+y)' = x'y' In other words just take the complement of each individual term and change the AND to an OR (or vice versa). So, for the complement of AB': (AB')' = A'+ B (complement each term and change the AND to an OR) Let: A = "I am stupid" B = "I am tall" Then: AB' = "I am stupid and I am not tall" The complement of the above statement could be read something like: (AB')' = A' + B = "Either I am not tall or I am stupid" BTW - for me, AB :lol: Perion
Thank you very much for your help, now it make sence here you can see my teacker's answer: NOT(A and (NOT B)) = NOT A or NOT(NOT B) = NOT A or B (AB) = a + (B) = A + B But he was unable to explain it :angry: Again thx. Tommy BTW you might be tall - but I don't believe that you are stupid !! tommy