How Does the Function $f(x) = \frac{1}{g(x)}$ Behave?

  • Context: MHB 
  • Thread starter Thread starter karush
  • Start date Start date
  • Tags Tags
    Parabola
Click For Summary
SUMMARY

The function $f(x) = \frac{1}{g(x)}$ is analyzed with $g(x) = (x-2)^2 - 1$. The domain of $f(x)$ is determined to be $(-\infty, 1) \cup (1, 3) \cup (3, \infty)$, as $g(x)$ has roots at $x=1$ and $x=3$, leading to vertical asymptotes. The horizontal asymptote of $f(x)$ is established at $y=0$, as the limits of $f(x)$ approach zero when $x$ approaches positive or negative infinity. Additionally, $f(x)$ shares the same sign as $g(x)$ throughout its domain.

PREREQUISITES
  • Understanding of function behavior and asymptotes
  • Knowledge of polynomial functions and their graphs
  • Familiarity with limits and continuity in calculus
  • Ability to analyze rational functions
NEXT STEPS
  • Study the properties of rational functions and their asymptotic behavior
  • Learn about polynomial function transformations and their impacts on graphs
  • Explore the concept of limits in calculus, particularly at infinity
  • Investigate the relationship between the signs of functions and their inverses
USEFUL FOR

Students and educators in mathematics, particularly those focusing on calculus and function analysis, as well as anyone needing to understand the behavior of rational functions and their asymptotes.

karush
Gold Member
MHB
Messages
3,240
Reaction score
5
The graph of $y=(x-2)^2 - 1$ is given, then they say use this graph for problem 7

Next is
7) $f(x) =\frac{1} {g(x)} $ ?
Step one restrictions $y> \ge - 1$
Step two Equation Solution?
Step three: Domain:= $\left(-\infty, +\infty\right)$
Vertical Asymptopes at: none

What's with the?
 
Physics news on Phys.org
I am assuming we have:

$$g(x)=y=(x-2)^2-1$$

and then:

$$f(x)=\frac{1}{g(x)}$$

If I was then going to look for the domain of $f$, I would observe that it will be all reals, with the exception of the roots of $g$ (where $g$ will have vertical asymptotes):

$$g(x)=(x-2)^2-1=(x-2+1)(x-2-1)=(x-1)(x-3)=0$$

Thus, the domain of $f$ is:

$$(-\infty,1)\,\cup\,(1,3)\,\cup\,(3,\infty)$$

We can also observe that:

$$\lim_{x\to\pm\infty}g=\infty\implies \lim_{x\to\pm\infty}f=0$$

And so there is a horizontal asymptote at $y=0$.

We also know that $f$ has the same sign as $g$.

I don't know what is meant by "Equation Solution."
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
1
Views
1K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K