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$(p\vee q)$ $\wedge$ $(p\wedge q)' \equiv ? $

I wanna find what this equivalent to. So my teacher has solved this but If it's possible, wanna get a solution which i can understand easily.

My idea (I mean my teacher :P):

$\equiv p \vee q$

Regards!

Lan
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3 Answers3

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$$(p \lor q) \land (p \land q)'\equiv (p \lor q)\land (p' \lor q')\tag{DeMorgan's}$$

Now, distribute:

$$\begin{align}(p \lor q)\land (p' \lor q')& \equiv \Big((p \land (p'\lor q')) \lor (q \land (p'\lor q'))\Big)\\ \\ & \equiv [\underbrace{(p \wedge p')}_{\bot = 0}\vee (p \wedge q')]\vee [(q \wedge p')\vee (\underbrace{q\wedge q')}_{\bot = 0}]\tag{Distribution again}\\ \\ & \equiv (p \land q') \lor (p' \land q)\end{align}$$

This is, if you're familiar with it, $p \operatorname{XOR} q$

amWhy
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\begin{eqnarray*} (p\vee q) \wedge (p\wedge q)' &\equiv & (p\vee q) \wedge (p'\vee q')\\ & \equiv& [p \wedge (p'\vee q')]\vee [q \wedge (p'\vee q')]\\ & \equiv & [(p \wedge p')\vee (p \wedge q')]\vee [(q \wedge p')\vee (q\wedge q')] \\ & \equiv & (p \wedge q')\vee (q \wedge p') \end{eqnarray*}

nonuser
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Read it in English: "P or Q but not both" ... that's the exclusive or!

Bram28
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