Question

Show that (p V q) A (¬ p V r) -> (q V r) is a tautology.

Answer 1

i made the truth table :

Answer 2

Then you've shown that it is a tautology :)

Answer 3

whew, i am glad i didn't have to type that
you are done

Answer 4

Are you supposed to prove it by some other method?

Answer 5

yup

Answer 6

By identities?

Answer 7

hold on bro

Answer 8

In the place of click to list you can either put true or false

Answer 9

this tautology is called resolution. it is one of the rules of inference.

Answer 10

hmm

Answer 11

i m confused

Answer 12

well, look at the first box

Answer 13

ok

Answer 14

if the conclusion is q or r, when will that be true?

Answer 15

just consider q or r alone

Answer 16

it is true everytime except when both of em are false

Answer 17

right, so that answers the first 2 boxes

Answer 18

ok then

Answer 19

anybody wanna help ? -_-