An argument form is valid if, no matter what particular statements are substituted for the statement variables in its premises, whenever the resulting premises are all true, the conclusion is also true. (Hint: **If any premises are false, then the argument is vacuously true**.)

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## Can a true argument be invalid?

TRUE: **A valid argument cannot possibly have all true premises and a false conclusion**. If some argument really does have all true premises and a false conclusion, then it is obviously possible for such an argument to have true premises and a false conclusion. So the argument is invalid.

## Is a statement vacuously true?

In logic, statements of type **if P, then Q are said to be vacuously true when the proposition P is false**. For example, the statement, if sun rises in the north then everyone gets 100 percent in final exam, is a true statement since the proposition “sun rises in the north” is false.

## How do you know if an argument is valid or invalid?

Valid: **an argument is valid if and only if it is necessary that if all of the premises are true, then the conclusion is true**; if all the premises are true, then the conclusion must be true; it is impossible that all the premises are true and the conclusion is false. Invalid: an argument that is not valid.

## Can an argument be true and valid?

It is important to stress that the premises of an argument do not have actually to be true in order for the argument to be valid. An argument is valid if the premises and conclusion are related to each other in the right way so that if the premises were true, then the conclusion would have to be true as well.

## Which of the following is not a valid argument?

Answer: Valid: an argument is valid if and only if it is necessary that if all of the premises are true, then the conclusion is true; if all the premises are true, then the conclusion must be true; it is impossible that all the premises are true and the conclusion is false. Invalid: **an argument that is not valid**.

## What is an example of a valid argument?

A valid argument is an argument in which the conclusion must be true whenever the hypotheses are true. In the case of a valid argument we say the conclusion follows from the hypothesis. For example, consider the following argument: “**If it is snowing, then it is cold.** **It is snowing.**

## Can an invalid argument have true premises and true conclusion?

**Invalidity is a no guarantee of a true conclusion when the premises are true**. True premises can lead to either a true or a false conclusion in an invalid argument. In these examples, luck rather than logic led to the true conclusion.

## What are the valid argument forms?

**Valid propositional forms**

- Modus ponens.
- Modus tollens.
- Hypothetical syllogism.
- Disjunctive syllogism.
- Constructive dilemma.

## How do you tell if an argument is valid using a truth table?

Remember that an argument is valid **if it is impossible for the premises to be true and the conclusion to be false**. So, we check to see if there is a row on the truth table that has all true premises and a false conclusion. If there is, then we know the argument is invalid.

## How do you verify a truth table?

To verify the truth table of a logic gate, **the suitable IC is taken and the connections are given using the circuit diagram**. For all the ICs, 5V is applied to the pin 14 while the pin 7 is connected to the ground. The logical inputs of the truth table are applied and the corresponding output is noted.

## What is NOT gate truth table?

Truth table is a table that gives output for all possible combinations of inputs to a logic circuit. NOT GATE: **A logic gate which performs the function of logical operator NOT is called as NOT gate**. Some of the function of NOT gate are as follow: It performs a basic logic function called inversion or complementation.

## What is De Morgan’s first theorem?

DeMorgan’s first theorem states that **two (or more) variables NOR´ed together is the same as the two variables inverted (Complement) and AND´ed**, while the second theorem states that two (or more) variables NAND´ed together is the same as the two terms inverted (Complement) and OR´ed.

## What is NAND truth table?

The NAND gate is **a combination of an AND gate and NOT gate**. They are connected in cascade form. It is also called Negated And gate. The NAND gate provides the false or low output only when their outputs is high or true.

## Is the NAND operator associative?

The NAND and NOR functions are the complements of AND and OR functions respectively. They are commutative, but **not associative**. So these functions can not be extended to multiple input variables very simply.

## Does NAND equal or?

**A NAND gate is equivalent to an inverted-input OR gate**. An AND gate is equivalent to an inverted-input NOR gate. A NOR gate is equivalent to an inverted-input AND gate. An OR gate is equivalent to an inverted-input NAND gate.

## Why NAND gates are preferred?

In general, cells are designed to have similar drive strength of pull up and pull down structures to have comparable rise and fall time. **NAND gate has better ratio of output high drive and output low drive as compared to NOR gate**. Hence NAND gate is preferred over NOR.

## Which logic gate is fastest?

**Emitter-coupled-logic (ECL)** is a BJT logic family that is generally considered the fastest logic available.

## Why is NAND gate the fastest?

If you take a look at the NAND gate schematic NMOS is in series and in NOR gate schematic NMOS is in parallel. **since NMOS is in series in NAND**, NAND gate iss faster and is usually preferred.