Find the difference quotient and simplify your answer.

[tex]\[ f(x) = x^2 - 2x + 1 \][/tex]

[tex]\[ \frac{f(4+h) - f(4)}{h}, \quad h \neq 0 \][/tex]



Answer :

To find the difference quotient for the function [tex]\( f(x) = x^2 - 2x + 1 \)[/tex], we need to follow a series of steps. Let's go through them in detail.

### Step 1: Compute [tex]\( f(4) \)[/tex]

First, we substitute [tex]\( x = 4 \)[/tex] into the function [tex]\( f(x) \)[/tex]:
[tex]\[ f(4) = 4^2 - 2 \cdot 4 + 1 = 16 - 8 + 1 = 9 \][/tex]

### Step 2: Compute [tex]\( f(4 + h) \)[/tex]

Next, we substitute [tex]\( x = 4 + h \)[/tex] into the function [tex]\( f(x) \)[/tex]:
[tex]\[ f(4 + h) = (4 + h)^2 - 2(4 + h) + 1 \][/tex]
Expanding the expression, we get:
[tex]\[ (4 + h)^2 = 16 + 8h + h^2 \][/tex]
[tex]\[ -2(4 + h) = -8 - 2h \][/tex]
Combining these terms, we obtain:
[tex]\[ f(4 + h) = 16 + 8h + h^2 - 8 - 2h + 1 = h^2 + 6h + 9 \][/tex]

### Step 3: Form the difference quotient [tex]\( \frac{f(4 + h) - f(4)}{h} \)[/tex]

Now, we substitute [tex]\( f(4 + h) \)[/tex] and [tex]\( f(4) \)[/tex] into the difference quotient formula:
[tex]\[ \frac{f(4 + h) - f(4)}{h} = \frac{(h^2 + 6h + 9) - 9}{h} \][/tex]
Simplify the expression in the numerator:
[tex]\[ \frac{h^2 + 6h + 9 - 9}{h} = \frac{h^2 + 6h}{h} \][/tex]
Factor out [tex]\( h \)[/tex] in the numerator:
[tex]\[ \frac{h(h + 6)}{h} \][/tex]
Since [tex]\( h \neq 0 \)[/tex], we can cancel [tex]\( h \)[/tex] in the numerator and the denominator:
[tex]\[ h + 6 \][/tex]

So, the simplified form of the difference quotient is:
[tex]\[ \frac{f(4 + h) - f(4)}{h} = h + 6 \][/tex]

Conclusively, the simplified form of the difference quotient for the function [tex]\( f(x) = x^2 - 2x + 1 \)[/tex] at [tex]\( x = 4 \)[/tex] is:
[tex]\[ h + 6 \][/tex]

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