Math Problem Statement

Find and simplify

f(a + h) − f(a)

h

,    (h ≠ 0)

for the following function.

f(x) = 2x2 − 2x + 7

Solution

We need to find and simplify the expression

f(a+h)f(a)h\frac{f(a + h) - f(a)}{h}

for the function f(x)=2x22x+7f(x) = 2x^2 - 2x + 7, where h0h \neq 0.

Step 1: Compute f(a+h)f(a + h)

Substitute x=a+hx = a + h into the function f(x)=2x22x+7f(x) = 2x^2 - 2x + 7: f(a+h)=2(a+h)22(a+h)+7f(a + h) = 2(a + h)^2 - 2(a + h) + 7 Expand (a+h)2(a + h)^2: (a+h)2=a2+2ah+h2(a + h)^2 = a^2 + 2ah + h^2 Now substitute back: f(a+h)=2(a2+2ah+h2)2(a+h)+7f(a + h) = 2(a^2 + 2ah + h^2) - 2(a + h) + 7 Distribute the terms: f(a+h)=2a2+4ah+2h22a2h+7f(a + h) = 2a^2 + 4ah + 2h^2 - 2a - 2h + 7

Step 2: Compute f(a)f(a)

Substitute x=ax = a into the function: f(a)=2a22a+7f(a) = 2a^2 - 2a + 7

Step 3: Subtract f(a)f(a) from f(a+h)f(a + h)

Now subtract f(a)f(a) from f(a+h)f(a + h): f(a+h)f(a)=(2a2+4ah+2h22a2h+7)(2a22a+7)f(a + h) - f(a) = (2a^2 + 4ah + 2h^2 - 2a - 2h + 7) - (2a^2 - 2a + 7) Simplify by canceling like terms: f(a+h)f(a)=4ah+2h22hf(a + h) - f(a) = 4ah + 2h^2 - 2h

Step 4: Divide by hh

Now divide by hh: f(a+h)f(a)h=4ah+2h22hh\frac{f(a + h) - f(a)}{h} = \frac{4ah + 2h^2 - 2h}{h} Factor out hh from the numerator: f(a+h)f(a)h=h(4a+2h2)h\frac{f(a + h) - f(a)}{h} = \frac{h(4a + 2h - 2)}{h} Since h0h \neq 0, we can cancel out hh: f(a+h)f(a)h=4a+2h2\frac{f(a + h) - f(a)}{h} = 4a + 2h - 2

Final Answer:

The simplified expression is:

f(a+h)f(a)h=4a+2h2\frac{f(a + h) - f(a)}{h} = 4a + 2h - 2

Would you like further details or have any questions about the process?

Here are 5 questions related to the topic:

  1. What is the significance of the expression f(a+h)f(a)h\frac{f(a + h) - f(a)}{h} in calculus?
  2. How would the answer change if f(x)f(x) had an additional linear term?
  3. Can you explain the role of the limit as hh approaches 0 in finding the derivative?
  4. How do we expand binomials like (a+h)2(a + h)^2?
  5. What would the expression look like if f(x)f(x) was a cubic function?

Tip: In calculus, the expression f(a+h)f(a)h\frac{f(a + h) - f(a)}{h} is key to understanding the concept of derivatives. It represents the average rate of change of the function over the interval from aa to a+ha + h.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Function Evaluation

Formulas

Derivative definition

Theorems

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Suitable Grade Level

Grades 11-12