# Fuction help!!!

• February 27th 2009, 09:56 AM
lucy2284
Fuction help!!!
I need some help with function problems. Thanks!!!

1. find the domain of p(x)=(x^2-2x/x-1) all under a square root sign.
I was thinking that x could not equal 1,2 the 1 would make the denominator 0 and the 2 would make the numerator 0. So I have no idea because it wasn't the right answer at all.

2. Given the function f(x)=1/x+1
find the following expression and simplfy: f(a+h)-f(a)/h

Given that:
f(a+h)=1/a+h+1
f(a)=1/a+1

3. Find the average rate of change of the function f(t)=(t)^1/2 so t square rooted. between t=a and t=a+t

I got to here

((a)^1/2-(a+h)^1/2)/(a-a+h)

I know that in the denominator the a's cancel out leaving h, but I have no idea what to do with the top.

For these problems I need help finding the domain and range. I guess I don't really understand the range either.

1. f(x)=x^2+1
what is the Domain and range?

2. f(x)=x^2+1 given the restriction -1<or equal x <or equal 5
The domain is [-1,5]
what is the range?
is there a simple way to figure this out?
• February 27th 2009, 12:51 PM
mr fantastic
Quote:

Originally Posted by lucy2284
I need some help with function problems. Thanks!!!

1. find the domain of p(x)=(x^2-2x/x-1) all under a square root sign.
I was thinking that x could not equal 1,2 the 1 would make the denominator 0 and the 2 would make the numerator 0. So I have no idea because it wasn't the right answer at all.

2. Given the function f(x)=1/x+1 Mr F says: Is it (1/x) + 1 or 1/(x+1)?
find the following expression and simplfy: f(a+h)-f(a)/h

Given that:
f(a+h)=1/a+h+1
f(a)=1/a+1

3. Find the average rate of change of the function f(t)=(t)^1/2 so t square rooted. between t=a and t=a+t Mr F says: Should this be t = a + h?

I got to here

((a)^1/2-(a+h)^1/2)/(a-a+h)

I know that in the denominator the a's cancel out leaving h, but I have no idea what to do with the top. Mr F says: Do nothing. Becuase there's nothing to do.

For these problems I need help finding the domain and range. I guess I don't really understand the range either.

1. f(x)=x^2+1
what is the Domain and range?

Mr F says: Draw a graph of this parabola to see what each will be. The range is all possible values of y.

2. f(x)=x^2+1 given the restriction -1<or equal x <or equal 5
The domain is [-1,5]
what is the range?

Mr F says: Again, draw a graph of this parabola over the given domain to see what each will be. The range is all possible values of y.

is there a simple way to figure this out?

1. You require the solution to $\frac{x^2-2x}{x-1} \geq 0$ where $x \neq 1$.
• February 27th 2009, 01:45 PM
lucy2284
re:help for functions
2. Given the function f(x)=1/x+1 Mr F says: Is it (1/x) + 1 or 1/(x+1)? It is 1/(x+1) sorry about the confusion.
find the following expression and simplfy: f(a+h)-f(a)/h

Given that:
f(a+h)=1/a+h+1
f(a)=1/a+1

1. find the domain of p(x)=(x^2-2x/x-1) all under a square root sign.
I was thinking that x could not equal 1,2 the 1 would make the denominator 0 and the 2 would make the numerator 0. So I have no idea because it wasn't the right answer at all.

1. You require the solution to http://www.mathhelpforum.com/math-he...c0c28ec9-1.gif where http://www.mathhelpforum.com/math-he...91daad0b-1.gif. I was confused by this??? That question was all under a square root.
• February 27th 2009, 02:48 PM
mr fantastic
Quote:

Originally Posted by lucy2284
2. Given the function f(x)=1/x+1 Mr F says: Is it (1/x) + 1 or 1/(x+1)? It is 1/(x+1) sorry about the confusion.
find the following expression and simplfy: f(a+h)-f(a)/h

Given that:
f(a+h)=1/a+h+1
f(a)=1/a+1

1. find the domain of p(x)=(x^2-2x/x-1) all under a square root sign.
I was thinking that x could not equal 1,2 the 1 would make the denominator 0 and the 2 would make the numerator 0. So I have no idea because it wasn't the right answer at all.

1. You require the solution to http://www.mathhelpforum.com/math-he...c0c28ec9-1.gif where http://www.mathhelpforum.com/math-he...91daad0b-1.gif. I was confused by this??? That question was all under a square root.

The square root can only operate on numbers that are greater than or equal to zero. The square root is operating on $\frac{x^2-2x}{x-1}$. Therefore ....