• Support PF! Buy your school textbooks, materials and every day products Here!

Function Homework Help

  • Thread starter jai6638
  • Start date
  • #1
263
0
Q) Given F(X) = 1/x and (f/g)(x) = (x+1)/(x^2-x). find the function g.

A: (x+1)/x(x-1) = (1/x) . (x+1)/(x-1)

Hence, the function G is (x+1)/(x-1)


Is this answer correct?
 

Answers and Replies

  • #2
HallsofIvy
Science Advisor
Homework Helper
41,833
955
Almost! You have shown that [itex]\frac{x+1}{x^2- x}= \frac{x+1}{x(x-1)}= \frac{1}{x}\left(\frac{x+1}{x-1}\right)= f(x)\left(\frac{x+1}{x-1}\right)[/itex] correctly.

But you want f/g, not f*g! How do you divide by a fraction?
 
  • #3
263
0
So that would be (1/x) / (x+1)(x-1) = (x-1) / ( x^2+x)

Is that the correct answer?


thanks
 
  • #4
VietDao29
Homework Helper
1,423
2
Nope, that's still wrong. You can recheck your calculation.
g(x) = f(x) / ((f / g)(x))
By the way, at your first post, it reads F(x) = 1 / x. Do you really mean that or f(x) = 1 / x?
Viet Dao,
 
  • #5
HallsofIvy
Science Advisor
Homework Helper
41,833
955
What I wrote before was
[tex]\frac{x+1}{x^2- x}= \frac{x+1}{x(x-1)}= \frac{1}{x}\left(\frac{x+1}{x-1}\right)= f(x)\left(\frac{x+1}{x-1}\right)= \frac{f(x)}{g(x)}[/tex]

So [tex]\frac{1}{g(x)}= \frac{x+1}{x-1}[/tex].

Now do you see what g(x) is?

Once again, how do you divide by a fraction?
 
Last edited by a moderator:
  • #6
263
0
damn.... So does g(x) = (x-1)/(x+1) ?



By the way, at your first post, it reads F(x) = 1 / x. Do you really mean that or f(x) = 1 / x?
I mean, f(x)=1/x
 
Last edited:
  • #7
VietDao29
Homework Helper
1,423
2
Yup. That's correct.
Viet Dao,
 

Related Threads on Function Homework Help

  • Last Post
Replies
9
Views
1K
  • Last Post
Replies
2
Views
844
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
10
Views
2K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
12
Views
2K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
1
Views
2K
Top