How do you find and simplify the difference quotient for the function f(x) = x² + 5, where h is not equal to zero?

To find and simplify the difference quotient for the function f(x) = x² + 5, we follow these steps:

  1. Recall the definition of the difference quotient:

    The difference quotient is given by the formula:

    Difference Quotient = \\frac{f(x + h) – f(x)}{h}

  2. Calculate f(x + h):

    We start by substituting x + h into the function:

    f(x + h) = (x + h)² + 5 = x² + 2xh + h² + 5

  3. 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

  4. Substitute into the difference quotient formula:

    Now, we can substitute our result into the difference quotient:

    Difference Quotient = \\frac{2xh + h²}{h}

  5. 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.

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