This content introduces the concept of variables in mathematical language and explores different types of mathematical statements, including unconditional, existential, universal conditional, universal existential, and existential universal statements.
now we are going to discuss for the
another topic under the mathematical
language and symbols that is variables
okay so
what is variables it is represented by a letter
letter
z
y or
a n or a and b
as a symbol
example for example so we is there a
number with the
following property so doubling it and
adding three gives the same result as
so then is there a
number x
with the property that 2x
plus 3
is equal to x squared
double double
doubling it and adding 3 gives the same
result as squaring it
or is there a number of x with the
property that um
is there a number to check nothing
to illustrate the second use of the
variables considered statements no
matter what number might be chosen if it
is greater than two then square is
greater than four
don't hide a new numbering animal
okay so
introducing a variable to give a
temporary name to the number that you
might choose enables you to maintain the generality
generality
of this statement
is there a number x with the property
that 2x plus 3 is equal to x squared
so no matter what number might be chosen
if it's greater than 2 then its square
is greater than four
four
you know
no matter what number
might be chosen
if x is greater than two
then x squared is greater than four
writing a sentence using variables so
use variables to rewrite the following
sentence more formally so
so
are there numbers with the property the
sub that sum that the sum of their
squares equals so the
square of their sum
sum or
or
give any real number its square is non-negative
non-negative
checking
are there a number x and y
with the property of x squared plus y
squared is equal to quantity of x plus y
are there numbers
numbers
sentences such that x squared plus y
squared is equal to quantity of x plus y
or do there exist any numbers
x and y such that x squared plus y
squared is equal to quantity x plus y
for letter b
give any real number so r squared is none
none
negative so for any real numbers that r
r is equal r squared is greater than or
or for all real number or is r squared
is greater than or equal to zero
actually there are
so some important kinds of mathematical statements
statements
all positive numbers are greater than zero
are greater than zero
so unconditional statement says if one
thing is true
then some other thing also has to be true
true
for example if 378 is divisible by 18
and i'm not saying this is divisible so
if i think this is true
lyon then three seven eight is divisible
by six so
so
existential statement
says that there is at least one thing
for which
the property is true for example
while for the universal conditional
statement so a statement that is bought
universal and conditional so this will
be a combination of universal and
conditional statement for all animals a if
if
a is a dog then a is a mammal so they
can be written in ways that make them
appear to be purely universal or purely
conditional so statement
so if a is a dog
then a is a mammal so purely condition aliba
aliba so
so don
don
or if an animal is a dog then the animal
so for example
if a real number is not zero then each
square is anna
yeah
you know
onion number one yes
yes
it's a facility
for all non-zero
real number is x
and that's a good
yeah you're right that is x squared is positive
positive
okay if x blank then blank
if x is a nonzero real number then
then
so for the universal existential
statements so a statement that is
universal because its first part says
that a certain property is true for all
objects of a given type and it is ex
existential because its second part
asserts the existence of something
for example every every real number has
an additive inverse
all real numbers have an added
let's have an additive real numbers for
all real numbers or there is an additive inverse
inverse
for all real numbers are there is a real
number such as on s such as s is an additive
additive inverse
inverse
so you know adding
okay next so
for this statement that is existential
because its first part asserts
that a certain object is exists and is
universal because its second part says
that the object satisfy a certain
property for all things of a certain kind
kind
for example we have there is a positive
integer that is less than or equal to
i hope
may join us on the new acting lecture
for the variables so
so
not we're going to discuss for another
topic under the
mathematical language
so i hope nintendo ciao
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