Answer
Let the domain consist of y and z for which
P(y) is false
Q(y) is true
P(z) is true
Q(z) is false.
$\exists xP(x) \land \exists x Q(x)$ is then true (because $\exists xP(x)$ and $\exists xQ(x)$ is true) and $\exists x(P(x) \land Q(x))$ ls false (since $P(x)$ and $Q(x)$ are never true at the same time).
Since the two expressions do not have the same truth value for this case, the two expressions can’t be logically equivalent.
Work Step by Step
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