Question 148844
Determine whether the argument is valid or invalid. 

A tree has green leaves or the tree does not produce oxygen.
This tree has green leaves
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 This tree does not produce oxygen. 
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Let p be "A tree has green leaves ; Let q be "the tree does not produce oxygen"
[(p  OR   q) AND p] implies q
..T....T...T...T...T.....T.....T
..T....T...F...F...T.....T.....F
..F....T...T...F...F.....T.....T
..F....F...F...F...F.....T.....F

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The p and q columns are standard
Form the OR of q and q
Form the AND of OR and p
Form the implies of AND and q
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As you can see in the "implies" column, the argument is valid for all p/q
conditions. The argument is valid.
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Cheers,
Stan H.