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Math Help - Is this argument valid?

  1. #1
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    Is this argument valid?

    I have to find out whether this argument is valid or invalid:

    p -> q
    (q v ([not]r)) -> (p [and] s)
    s->(r v q)

    Hope that makes sense, and also I appreciate any help that can be offered. Thanks.
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  2. #2
    Member Jones's Avatar
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    Quote Originally Posted by GreenDay14 View Post
    I have to find out whether this argument is valid or invalid:

    p -> q
    (q v ([not]r)) -> (p [and] s)
    s->(r v q)

    Hope that makes sense, and also I appreciate any help that can be offered. Thanks.
    If im not mistaken it's valid.

    You can check for yourself, if you find values for s,r,p and q that makes the result false but the statements true, then the argument is invalid
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  3. #3
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    Hello GreenDay14
    Quote Originally Posted by GreenDay14 View Post
    I have to find out whether this argument is valid or invalid:

    p -> q
    (q v ([not]r)) -> (p [and] s)
    s->(r v q)

    Hope that makes sense, and also I appreciate any help that can be offered. Thanks.
    I've drawn up a truth table for the proposition

    ((p \rightarrow q)\land((q\lor \neg r)\rightarrow(p\land s)))\rightarrow(s\rightarrow (r\lor q))

    - see attachment.

    The columns are evaluated in order (1) through (8) - (8) being the final output. Since this show TRUE in every row, then, yes the argument is valid.

    Grandad
    Attached Thumbnails Attached Thumbnails Is this argument valid?-untitled.jpg  
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