Question

Can someone prove to me the De Morgans law

Answer 1

the opposite of something is its opposite?

(AnB)' = A'uB'

that demorgans law?

Answer 2

and by proof, what means do you have avaiable to you for a proof? venns, truth tables, algebra for logic?

Answer 3

Is that the De Morgans Law

Answer 4

your post assumes that you already know what demorgans law states.

Answer 5

http://mathworld.wolfram.com/deMorgansLaws.html

Answer 6

No, I don't know what is De Morgans Law

Answer 7

then you really cany prove what you do not know :) and the way you prove it will depend on the methods that you have been exposed to.

Answer 8

ah okay thanks. I will study it first. Thaksyou again

Answer 9

yw, and once we know what youre working with: venn diagrams, or truth tables, or some other methods. we will be able to process a proof.

Answer 10

okay. I know the truth table

Answer 11

the truth table is then determining the run for A and B, or p and q is usually a truth table setup

(puq)' = p' n q'

p p' q q' (puq) (puq)' p'nq'
t f t f t f f
t f f t t f f
t f t f t f f
t f f t t f f
f t t f t f f
f t f t f t t
...
etc

if the last 2 columns are exactly alike, then you have proofed it

you would also want to run the: (pnq)' = p' u q' to verify both conditions

Answer 12

Thanks a lot. But how about prove the right distributive Law of (B u C) n A = (B n A) u (C n A)

Answer 13

if all you know is truth tables, then its just a matter of playing the field with it

define a b c (buc) (buc)na and the rest of it

build up the parts in order to work them out as a whole, then compare the two columns that need to be equal

Answer 14

ah i get it. Okay i will try. Thanks

Answer 15

youre welcome, and good luck with it :)

Answer 16

Thanks :D