Recent content by pwhitey86

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    I think i want to try linux out

    solidworks in wine... not yet Check out the wine app db: not quite there yet: extruding crashes it http://appdb.winehq.org/objectManager.php?bShowAll=true&bIsQueue=false&bIsRejected=false&sClass=version&sTitle=&sReturnTo=&iId=8983
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    How do you prove things with null

    For instance, the following seems obvious but I don't know how to state the proof formally (and directly): Show A \cap (B-A) = \{\} Here is a try: For any x \in U \ if \ x \in A then x \notin (B-A) therefore A \cap (B-A) = \{\} there is something missing...
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    Is This a Valid Proof by Contradiction for Set Theory?

    Here is a go at a direct proof: A\cap B = \{\} \Leftrightarrow \forall x \in U \ \ x \notin A\cap B \Leftrightarrow x \in (A\cap B)^c \Leftrightarrow x \in A^c\cup B^c Now suppose x \in A then x \in B^c and \Leftrightarrow A \subseteq B^c is this correct? is this what you meant by...
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    Is This a Valid Proof by Contradiction for Set Theory?

    Hi. I am new to formal proofs. Is the following a legitimate method for proving this assertion by contradiction. Show A\cap B = \{\} \Leftrightarrow A \subseteq B^c If A\cap B \neq \{\} then \exists \ x \ ST \ x \in A \ AND \ x \in B Since x \in A \ \ \ A \subseteq B^c...
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    Property of characteristic polynomial

    Hi, Why is it that if A is m×n-matrix and B is n×m matrices such that m<n, then AB is m×m and BA is n×n matrix. Then the following is true: pAB(t) = t^(m-n)*pBA(t) where pAB(t) and pBA(t) are characteristic polynomials of AB and BA thanks
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