What is a situation which seems false but is true?
Asked in Computer Programming, Math and Arithmetic
What is the result of True AND False OR True?
True AND False OR True evaluates to True. IT seems like it does not matter which is evaluated first as: (True AND False) OR True = False OR True = True True AND (False OR True) = True AND True = True But, it does matter as with False AND False OR True: (False AND False) OR True = False OR True = True False AND (False OR True) = False AND True = False and True OR False AND False: (True OR False) AND False = True AND False = False True OR (False AND False) = True OR False = True Evaluated left to right gives a different answer if the operators are reversed (as can be seen above), so AND and OR need an order of evaluation. AND can be replaced by multiply, OR by add, and BODMAS says multiply is evaluated before add; thus AND should be evaluated before OR - the C programming language follows this convention. This makes the original question: True AND False OR True = (True AND False) OR True = False OR True = True
Asked in Math and Arithmetic, Algebra, Geometry
How do you construct a truth table for parenthesis not p q parenthesis if and only if p?
Assuming that you mean not (p or q) if and only if P ~(PVQ)--> P so now construct a truth table, (just place it vertical since i cannot place it vertical through here.) P True True False False Q True False True False (PVQ) True True True False ~(PVQ) False False False True ~(PVQ)-->P True True True False if it's ~(P^Q) -->P then it's, P True True False False Q True False True False (P^Q) True False False False ~(P^Q) False True True True ~(P^Q)-->P True True False False
All parts of a true and false question must be true for the answer to be true?
Yes. If all the question's parts are true, then the answer is true. If all the question's parts are false, then the answer is false. If one of the question's parts is false and the rest true, then the answer is false. Logically, this is illustrated below using: A = True, B = True, C = True, D = False, E = False, F = False A and B and C = True D and E and F = False A and B and D = False If you add NOT, it's a bit more complicated. A and NOT(D) = True and True = True NOT(D) and D = True and False = False NOT(A) and NOT(B) = False and False = False Using OR adds another layer of complexity. A OR NOT(E) = True OR True = True NOT(D) OR D = True OR False = False NOT(A) OR NOT(B) = False OR False = False Logic is easy once you understand the rules.
Asked in Geometry
Do a polygon has a sides that are line segments true or false?
Asked in Woozworld
What are the answers in the woozwize challenge in woozworld?
Asked in Science, Computer Programming
Where do we use logical operators?
The four logical operators are AND, OR, XOR and NOT. These operators are used to evaluate operands composed of boolean expressions. A boolean expression is any expression that returns a boolean value. A boolean value is a data type of arbitrary length (dependant upon the implementation of the programming language) but is typically 8 bits in length. When all bits are off, the value is false but when all bits are on, the value is true. Thus 0x00 is false while 0xff is true. When evaluating a boolean expression, the operands of that expression need not themselves be boolean. For instance, given the following definition of a string: string s = "Hello world" The boolean expression s=="" returns 0x00 because s is not equal to an empty string but the expression s=="Hello world" returns 0xff because s is equal to "Hello world". NOT is a unary operator which has only one operand. If the operand evaluates false, then the return value is true. If the operand evaluates true, the return value is false. In other words we use the NOT operator to invert all the bits in the boolean value. Thus we can say that NOT (s=="") returns 0xff because s=="" evaluates false (s is not an empty string) and NOT (false) evaluates true. The other operators are binary operators with two operands. The "truth tables" for each of these operators are as follows: true AND true == true true AND false == false false AND true == false false AND false == false true OR true == true true OR false == true false OR true == true false OR false == false true XOR true == false true XOR false == true false XOR true == true false XOR false == false Note that AND returns true only when both operands evaluate true while OR returns true when one or both operands are true. XOR is the eXclusive-OR operator which only returns true when one (and only one) operand is true. You will note that there are 4 possible outcomes for each of these binary operators and that each of the tables produces a unique combination of true and false results depending on the two inputs (which are in the same order for each table). If we translate these results into binary values we can see that AND produces 1000 (true, false, false, false), OR produces 1110 (true, true, true, false) and XOR produces 0110 (false, true, true, false). With 4-bits there are clearly 16 possible combinations of 1 and 0 bits, but the logical operators only produce 3 of them. However, we can combine these three operators in various ways along with NOT to produce seven more tables: NOT (true AND true) = false NOT (true AND false) = true NOT (false AND true) = true NOT (false AND false) = true NOT (true OR true) = false NOT (true OR false) = false NOT (false OR true) = false NOT (false OR false) = true NOT (true XOR true) = true NOT (true XOR false) = false NOT (false XOR true) = false NOT (false XOR false) = true (NOT true) AND true = false (NOT true) AND false = false (NOT false) AND true = true (NOT false) AND false = false (NOT true) OR true = true (NOT true) OR false = false (NOT false) OR true = true (NOT false) OR false = true true AND (NOT true) = false true AND (NOT false) = true false AND (NOT true) = false false AND (NOT false) = false true OR (NOT true) = true true OR (NOT false) = true false OR (NOT true) = false false OR (NOT false) = true The remaining 6 tables are only of interest to academics and are not particularly useful to programmers. Those 6 are the truth tables that produce false regardless of input, or simply return the first operand, or the second operand, or the logical NOT of any of these three. It should be noted that some languages do not provide a logical operator for XOR. This is because XOR can be simulated using AND, OR and NOT. That is, given two inputs, a and b, a XOR b can be determined from (a AND (NOT b)) OR ((NOT a) AND b). It should also be noted that logical operators are not the same as bitwise logic operators. Bitwise logic operators work similarly to the logic operators in terms of the truth tables, but they compare on a bit-by-bit basis. Thus 0101 AND 0110 outputs 0100 because bit 2 is the only bit that is set in both inputs and is therefore the only bit that evaluates true according to the AND truth table. The NOT operator also works differently in that it flips all the bits in the operand, effectively returning the ones complement of its input (it is often referred to as the inverse operator for that reason). The logical bitwise operators are typically used to read and write the individual bits in a bit field (or bitmap). Such values are typically used to denote which features within a set of features are enabled or disabled. While this can save memory by cramming more booleans into a single word, the downside is that the data is slower to read and write because of the additional operations required to access the individual bits. However, some architectures are optimised to take advantage of this.
Asked in Brain Teasers and Logic Puzzles
Is 'This statement is false' true or false?
If the statement is false, then "This statement is false", is a lie, making it "This statement is true." The statement is now true. But if the statement is true, then "This statement is false" is true, making the statement false. But if the statement is false, then "This statement is false", is a lie, making it "This statement is true." The statement is now true. But if the statement is true, then... It's one of the biggest paradoxes ever, just like saying, "I'm lying right now."
What are Boolean operators and how are they used?
Boolean operators are used in programming. It would be hard for me to explain exactly how they are used in programming without giving you a programming course, but I can tell you basically what they do. The main boolean operators are AND, OR, NOT, and XOR (exclusive or). So: * (true AND true) makes true * (true AND false) makes false * (false AND true) makes false * (false AND false) makes false * (true OR true) makes true * (true OR false) makes true * (false OR true) makes true * (false OR false) makes false * (NOT true) make false * (NOT false) makes true XOR is the same as OR except that it only allows one or the other to be true; not both: * '''(true XOR true) makes false''' * (true OR false) makes true * (false OR true) makes true * (false OR false) makes false Boolean operators can be mixed together like this: NOT (true XOR (false AND true)) makes false In programming, you often use symbols to represent these instead of writing out the words. OR is , not is !, and AND is &&. -DJ Craig They are often used by search engines. If you put in "Bob" AND "Smith" you would get results that have both Bob and Smith in them (say 150 results). If you put in "Bob" OR "Smith" you would get any result with Bob or Smith (say 3000 results). If you put in "Bob" NOT "Smith" you would get Bob Jones, but not Bob Smith. Not all search engines use these. And some use other terms for them.
Asked in Microsoft Excel
What is done if function is one in which the action to be taken for the true or false case includes yet another If function?
You insert the second IF function into the first one, creating what is called a nested If. Another IF can be put in the True or False part of an existing IF function. In as situation where there is a need for another IF when the first condition is true, the structure could then be something like this: =IF(condition, IF(condition, true, false), false)) Note there are two brackets at the end, closing the two IF functions.
Asked in Color Blindness
Is a carrier for colorblindness colorblind true or false?
Asked in Electronics Engineering
What is xor gates?
Xor gates are a type of logical gate that returns true if both of the two inputs aretwo different Boolean (true/false) values. The xor gate is also called an "exclusive or" gate because one input has to be true to return true, but not both. Here is a table of input values and return values for an xor gate. Inputs | Return Value (Output) true and true | false true and false | true false and true | true false and false | false
Why is the statement 'This sentence is false' so confusing?
In the logical sense, sentences must be either true or false and not both. "This sentence is false" cannot be true because that would mean that it is false, and it cannot be both. It also cannot be false because that would mean that it is true, and it cannot be both. Therefore, if it is true or false, then it is both true and false. Therefore it is either neither true nor false or both true and false; therefore, in the logical sense, it is not a sentence. However, it says it is a sentence; therefore, it is lying; therefore, it is false.