👤

determine the domain in each rational function f(x)=2x/x+3

Sagot :

Step-by-step explanation:

Domain of function

f

(

x

)

=

2

x

x

3

is all real numbers except

3

.

Range is all real numbers except

2

.

Explanation:

Graph of

f

(

x

)

=

2

x

x

3

is

graph{2x/(x-3) [-20, 20, -10, 10]}

Domain, the set of argument values where the function is defined, is, obviously all real numbers except those where denominator

(

x

3

)

is zero, and it happened to be only

x

=

3

. So, for all

x

3

the function is defined and its domain is

x

3

.

One of the ways to determine the range of a function

f

(

x

)

is to consider a domain of an inverse function

f

1

(

x

)

. In our case, if

y

=

2

x

x

3

then

x

=

3

y

y

2

. Therefore, inverse function is

f

1

=

3

x

x

2

, and its domain is

x

2

. So, the range of the original function is all real numbers except

2

.

Actually, the number

2

is the limit our function is approaching as

x

tends to

+

or

.