Let and be two logical expressions. Then:

Question

Let  and  be two logical expressions. Then:

Canvas Classes · Accepted Answer

🧠 Test Each by Substitution to Find One That Fails

For , find a row where it is False. For , check whether it simplifies to .

.

Try :
- .
- .
- .
- OR: .

So . Not tautology.

.

Convert: . Tautology.

So  not tautology,  is tautology. Option (b).

This is the habit: to disprove a tautology, find a single counterexample row. To confirm a tautology, simplify to  algebraically.

🗺️ Working It Out

test at : all three pieces . So . Not tautology.

simplification: . Tautology.

So only  is a

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