Definitions

# What is a situation which seems false but is true?

###### Wiki User

###### 2017-12-04 01:53:02

A paradox.

## Related Questions

###### 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 Domestic Dogs

### How dogs are the best?

###### 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

###### Asked in Germany in WW2, Philosophy and Philosophers, Word Brain Teasers

### 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 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."

###### Asked in Computers, Computer Programming, Synonyms and Antonyms, Algebra

### 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 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

###### Asked in Math and Arithmetic, Brain Teasers and Logic Puzzles

### 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.