Math Problem Statement

f(x)=x-2/x+2 ;g(x)1/x,(f.g)(x)=,\left(f.g\right)\left(x\right)=

Solution

You want to find the composition of the functions f(x)=x2x+2f(x) = \frac{x - 2}{x + 2} and g(x)=1xg(x) = \frac{1}{x}, specifically (fg)(x)\left( f \circ g \right)(x). This notation represents f(g(x))f(g(x)).

To find (fg)(x)\left( f \circ g \right)(x), substitute g(x)=1xg(x) = \frac{1}{x} into the function f(x)f(x):

(fg)(x)=f(g(x))=f(1x)(f \circ g)(x) = f\left(g(x)\right) = f\left(\frac{1}{x}\right)

Given that f(x)=x2x+2f(x) = \frac{x - 2}{x + 2}, substitute 1x\frac{1}{x} for xx:

f(1x)=1x21x+2f\left(\frac{1}{x}\right) = \frac{\frac{1}{x} - 2}{\frac{1}{x} + 2}

Now, let's simplify this expression:

f(1x)=12xx1+2xxf\left(\frac{1}{x}\right) = \frac{\frac{1 - 2x}{x}}{\frac{1 + 2x}{x}}

Since the denominator xx cancels out:

f(1x)=12x1+2xf\left(\frac{1}{x}\right) = \frac{1 - 2x}{1 + 2x}

Therefore, the composition (fg)(x)\left( f \circ g \right)(x) is:

(fg)(x)=12x1+2x\left( f \circ g \right)(x) = \frac{1 - 2x}{1 + 2x}

Do you have any questions or would you like more details on this topic?


Here are some related questions you might find helpful:

  1. What is the domain of the composition (fg)(x)\left( f \circ g \right)(x)?
  2. How do you find the inverse of (fg)(x)\left( f \circ g \right)(x)?
  3. Can you determine the range of (fg)(x)\left( f \circ g \right)(x)?
  4. What happens if you compute the composition in the reverse order, (gf)(x)\left( g \circ f \right)(x)?
  5. How would you solve for xx if (fg)(x)=0\left( f \circ g \right)(x) = 0?

Tip: Always remember that when composing functions, you must consider the domains of both functions to ensure the composition is valid over the appropriate intervals.

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Math Problem Analysis

Mathematical Concepts

Functions
Composition of Functions
Rational Functions

Formulas

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Theorems

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Suitable Grade Level

High School