false and false is false logically. The result of an expression using the && operator is determined based on these rules: If the left side of the expression is “falsey”, the expression will return the left side.
Do two false make a true?
No. Formal logic (valid reasoning) guarantees only that from true statements, a false conclusion (statement) cannot be deduced. … It does not say that from false premisses a true conclusion cannot be reached (by a multiple logically invalid steps).
Why is if/p then q true when p is false?
The conditional of q by p is “If p then q” or “p implies q” and is denoted by p q. It is false when p is true and q is false; otherwise it is true. Contrapositive: … A conditional statement is logically equivalent to its contrapositive.
What is the truth value if p is true and q is false?
If p and q are propositions, the conjunction of p and q, p ∧ q, is true when both p and q are true, and is false otherwise. If p and q are propositions, the disjunction of p and q, p ∨ q, is false when both p and q are false, and is true otherwise. The symbol ≡ or ⇔ denotes equivalent truth value.
Is P → Q → [( P → Q → Q a tautology Why or why not?
(p → q) and (q ∨ ¬p) are logically equivalent. So (p → q) ↔ (q ∨ ¬p) is a tautology. … We have a number of rules for logical equivalence.
What does true/false mean?
true-false – offering a series of statements each of which is to be judged as true or false; “a true-false test” multiple-choice – offering several alternative answers from which the correct one is to be chosen; or consisting of such questions; “multiple-choice questions”; “a multiple-choice test”
What is a true or false statement?
A true-false statement is any sentence that is either true or false but not both. A negation of a statement has the opposite meaning of a truth value. A negations is written as ~p. If we call the statement: cucumbers are green, p then: p: cucumbers are green – this statement is true.
What is false or true?
True or false is variously said of something that must be considered as correct (true) or incorrect (false).
Why is 1 true and 0 false?
1 is considered to be true because it is non-zero. The fourth expression assigns a value of 0 to i. 0 is considered to be false. The fith expression assigns a value of 2 to i.
Does false && false return true?
Description :- Compares two expressions and returns true if one or both evaluate to true. Returns false only if both expressions are false.
What does false && false mean?
false && false = false only true && true = true.
What is implication truth table?
Truth Table of Logical Implication. An implication (also known as a conditional statement) is a type of compound statement that is formed by joining two simple statements with the logical implication connective or operator.
What is negation of implication?
Negation of an Implication.
The negation of an implication is a conjunction: ¬(P→Q) is logically equivalent to P∧¬Q. ¬ ( P → Q ) is logically equivalent to P ∧ ¬ Q .
What do you mean by propositional logic?
This is most easily done if we utilize a simplified logical language that deals only with simple statements considered as indivisible units as well as complex statements joined together by means of truth-functional connectives. We first consider a language called PL for “Propositional Logic”.
What makes the statement false?
A false statement is a statement that is not true. … A false statement need not be a lie. A lie is a statement that is known to be untrue and is used to mislead. A false statement is a statement that is untrue but not necessarily told to mislead, as a statement given by someone who does not know it is untrue.
How does one determine whether an explanation is true or false?
A statement is true if what it asserts is the case, and it is false if what it asserts is not the case. For instance, the statement “The trains are always late” is only true if what it describes is the case, i.e., if it is actually the case that the trains are always late.
How do you answer a true or false question?
5 Quick Tips for Answering True-or-False Test Questions
- Read the questions carefully. …
- Dissect the statement word-by-word and phrase-by-phrase. …
- Look for inflexible words. …
- Don’t become confused by negatives. …
- When all else fails, guess. …
- The Bottom Line on True-or-False Test Questions.
What does true and false mean in programming?
In computer programming, true is a boolean value that represents mathematical and logical truth. True is an important value in computing, because it is the basis of logical operations. There are two possible boolean values, true and false. If something is true, it is not false; if something is false, it is not true.
What are the advantages of true and false questions?
Advantages of True and False Questions:
- Can customize to use ‘Yes’ and ‘No’ or ‘I Disagree’ and ‘I Agree’
- Easy to grade on paper.
- Automatically graded online.
- Can be answered quickly by Test takers.
- Large range of content can be tested.
- Questions are easy to create.
What is tautology and contradiction?
A compound statement which is always true is called a tautology , while a compound statement which is always false is called a contradiction .
Are P → Q → R and P → Q → are logically equivalent?
Since columns corresponding to ¬(p∨q) and (¬p∧¬q) match, the propositions are logically equivalent. … Since columns corresponding to p∨(q∧r) and (p∨q)∧(p∨r) match, the propositions are logically equivalent. This particular equivalence is known as the Distributive Law.
What is a conditional statement that is false but has a true inverse?
Negating both the hypothesis and conclusion of a conditional statement. For example, the inverse of “If it is raining then the grass is wet” is “If it is not raining then the grass is not wet”. Note: As in the example, a proposition may be true but its inverse may be false.