Find the difference quotient [tex]\frac{f(x+h)-f(x)}{h}[/tex], where [tex]h \neq 0[/tex], for the function below.

[tex]\[ f(x) = \frac{x}{x-1} \][/tex]

Simplify your answer as much as possible.

[tex]\[ \frac{f(x+h)-f(x)}{h} = \][/tex]



Answer :

To find the difference quotient for the function [tex]\( f(x) = \frac{x}{x - 1} \)[/tex], we follow these steps:

1. Define [tex]\( f(x) \)[/tex]:
[tex]\[ f(x) = \frac{x}{x - 1} \][/tex]

2. Calculate [tex]\( f(x + h) \)[/tex]:
Substitute [tex]\( x + h \)[/tex] into the function:
[tex]\[ f(x + h) = \frac{x + h}{(x + h) - 1} = \frac{x + h}{x + h - 1} \][/tex]

3. Form the difference [tex]\( f(x + h) - f(x) \)[/tex]:
[tex]\[ f(x + h) - f(x) = \frac{x + h}{x + h - 1} - \frac{x}{x - 1} \][/tex]

4. Find a common denominator to combine the fractions:
[tex]\[ \frac{x + h}{x + h - 1} - \frac{x}{x - 1} = \frac{(x + h)(x - 1) - x(x + h - 1)}{(x + h - 1)(x - 1)} \][/tex]

5. Simplify the numerator:
Expand the terms in the numerator:
[tex]\[ (x + h)(x - 1) = x^2 - x + hx - h \][/tex]
[tex]\[ x(x + h - 1) = x^2 + hx - x \][/tex]
Therefore:
[tex]\[ (x^2 - x + hx - h) - (x^2 + hx - x) = -h \][/tex]

6. Combine the simplified numerator and denominator:
[tex]\[ \frac{f(x + h) - f(x)}{h} = \frac{\frac{-h}{(x + h - 1)(x - 1)}}{h} = \frac{-h}{h(x + h - 1)(x - 1)} \][/tex]

7. Cancel out [tex]\( h \)[/tex] in the numerator and denominator (since [tex]\( h \neq 0 \)[/tex]):
[tex]\[ \frac{-h}{h(x + h - 1)(x - 1)} = \frac{-1}{(x + h - 1)(x - 1)} \][/tex]

Thus, the simplified difference quotient is:
[tex]\[ \frac{f(x+h)-f(x)}{h} = \frac{-1}{(x + h - 1)(x - 1)} \][/tex]