To find and simplify the difference quotient for the function f(x) = x² + 5, we follow these steps:
- Recall the definition of the difference quotient:
The difference quotient is given by the formula:
Difference Quotient = \\frac{f(x + h) – f(x)}{h}
- Calculate f(x + h):
We start by substituting x + h into the function:
f(x + h) = (x + h)² + 5 = x² + 2xh + h² + 5
- Calculate f(x + h) – f(x):
Next, we find f(x + h) – f(x):
f(x + h) – f(x) = (x² + 2xh + h² + 5) – (x² + 5)
After simplification, we get:
f(x + h) – f(x) = 2xh + h²
- Substitute into the difference quotient formula:
Now, we can substitute our result into the difference quotient:
Difference Quotient = \\frac{2xh + h²}{h}
- Simplify:
Next, we simplify the expression:
Difference Quotient = 2x + h
Note that this simplification is valid for h ≠ 0, as division by zero is undefined.
Therefore, the simplified difference quotient for the function f(x) = x² + 5, where h is not equal to zero, is:
2x + h
This expression gives a good approximation of the function’s slope at the point x when h is small.