The correct answer of exercise 4 of chapter 1-1

[hosseinnedaee]

The above image shows the exercise 4 of the chapter1-1 so the solution would be:

$$ \begin{align*} \text{RT} &= \text{Ralph is tall.} \\ \text{ET} &= \text{Ed is tall.} \\ \text{RH} &= \text{Ralf is handsome.} \\ \text{EH} &= \text{Ed is handsome.} \end{align*} $$

(a)

$$ (RT \land ET) \lor (RH \land EH) $$

(b)

$$ (RT \lor RH) \land (ET \lor EH) $$

(c)

$$ \neg (RT \lor RH) \land \neg(ET \lor EH) $$

(d)

$$ \neg (RT \land RH) \land \neg (ET \land EH) $$