functions: finding domain of f(x) = (x to the 2 + x )/x+1

[isa]

how can i get the natural domain of a function? For example: f(x) = (x to the 2 + x )/x+1

I'm new so I don't know how to use the correct characters!

 

[pka]

Re: functions

Do you mean $\displaystyle f(x) = \frac{{x^2 + x}}{{x + 1}}$?

If so the domain is the set of all numbers such you do not divide by zero?
Tell us what that set is.

 

[Deleted member 4993]

Re: functions

how can i get the natural domain of a function? For example: f(x) = (x to the 2 + x )/x+1

I'm new so I don't know how to use the correct characters!

Please tell us the definition of domain of a function.

 

[isa]

This is all what the problem asks! Could you please help me??

 

[stapel]

This is all what the problem asks!

And to answer the exercise, you need first to know what the "domain" of a function is. What does your text say? :wink:

Thank you!

Eliz.

 

[pka]

Could you please help me??

Did you read my reply above?
Did that not help you?

 

[isa]

Sorry!. The exact question says:
Compare the natural domain of f and g.

f(x) = x^2+x / x+1 ; g(x)= x

 

[stapel]

Compare the natural domain of f and g.

f(x) = x^2+x / x+1 ; g(x)= x

Okay. Now what is the definition of "domain"? (You can't begin to do the comparison of the domains, until you know what a domain is, or how to find the domains of f and g.)

Please reply with your understanding of the term. Thank you!

Eliz.

 

[isa]

Okay. The Domain is the set of all real numbers (variable x) that define the function as real. The x values (input).

 

[Deleted member 4993]

Okay. The Domain is the set of all real numbers (variable x) that define the function as real. The x values (input).

So now figure out

for the function f(x) - are there any value of 'x' where f(x) will be undefined. If none, then domain of f(x) is (-inf., +inf). If you have 'x' values such that f(x) is undefined, then you would exclude those points from the infinite domain.

Similarly,

for the function g(x) - are there any value of 'x' where g(x) will be undefined. If none, then domain of g(x) is (-inf., +inf). If you have 'x' values such that g(x) is undefined, then you would exclude those points from the infinite domain.

 

[isa]

Thanks for your help!