Math Problem Statement

Use the figure to find the indicated derivatives, if they exist. Let h(x) = f(x) / g(x). Find h'(2), h'(3), and h'(4).

Solution

To solve the problem, let's analyze each part carefully using the information given on the graph.

Given:

  • h(x)=f(x)g(x)h(x) = \frac{f(x)}{g(x)}
  • We are asked to find the derivatives h(2)h'(2), h(3)h'(3), and h(4)h'(4) using the graph.

The derivative h(x)h'(x) of a quotient function h(x)=f(x)g(x)h(x) = \frac{f(x)}{g(x)} is given by the quotient rule: h(x)=f(x)g(x)f(x)g(x)[g(x)]2h'(x) = \frac{f'(x) g(x) - f(x) g'(x)}{[g(x)]^2} where f(x)f'(x) and g(x)g'(x) are the derivatives of f(x)f(x) and g(x)g(x), respectively.

Let's examine each part:

Part (a): Find h(2)h'(2)

  • Solution: From the graph, we determine f(2)f(2), g(2)g(2), f(2)f'(2), and g(2)g'(2).
    • f(2)=2f(2) = 2
    • g(2)=1g(2) = 1
    • f(2)1f'(2) \approx -1 (since f(x)f(x) has a slope of 1-1 at x=2x = 2)
    • g(2)=0g'(2) = 0 (since g(x)g(x) is flat at x=2x = 2)
    • Using the quotient rule: h(2)=f(2)g(2)f(2)g(2)[g(2)]2=(1)(1)(2)(0)12=1h'(2) = \frac{f'(2) g(2) - f(2) g'(2)}{[g(2)]^2} = \frac{(-1)(1) - (2)(0)}{1^2} = -1
    • Answer: h(2)=1h'(2) = -1 (This matches the correct answer already marked.)

Part (b): Find h(3)h'(3)

  • Solution: From the graph, we find f(3)f(3), g(3)g(3), f(3)f'(3), and g(3)g'(3).
    • f(3)=0f(3) = 0
    • g(3)=0g(3) = 0 (since both functions intersect the x-axis at x=3x = 3)
    • Because both f(3)=0f(3) = 0 and g(3)=0g(3) = 0, the function h(x)=f(x)g(x)h(x) = \frac{f(x)}{g(x)} is undefined at x=3x = 3, so h(3)h'(3) does not exist.
    • Answer: h(3)=DNEh'(3) = \text{DNE} (This also matches the correct answer.)

Part (c): Find h(4)h'(4)

  • Solution: Let's determine f(4)f(4), g(4)g(4), f(4)f'(4), and g(4)g'(4).
    • f(4)=1f(4) = 1
    • g(4)=2g(4) = 2
    • f(4)=1f'(4) = 1 (since f(x)f(x) has a slope of 11 at x=4x = 4)
    • g(4)=0g'(4) = 0 (since g(x)g(x) is flat at x=4x = 4)
    • Applying the quotient rule: h(4)=f(4)g(4)f(4)g(4)[g(4)]2=(1)(2)(1)(0)22=24=12h'(4) = \frac{f'(4) g(4) - f(4) g'(4)}{[g(4)]^2} = \frac{(1)(2) - (1)(0)}{2^2} = \frac{2}{4} = \frac{1}{2}
    • Answer: h(4)=12h'(4) = \frac{1}{2}

Let me know if you'd like further explanation on any part of the solution or if you have additional questions!


Related Questions:

  1. How is the quotient rule applied to find derivatives of function quotients?
  2. What happens if both the numerator and denominator equal zero at a given point?
  3. How do we interpret the slopes of piecewise functions from a graph?
  4. How would h(x)h(x) change if g(x)g(x) were to become negative?
  5. What is the significance of a point where h(x)h(x) is undefined in a derivative context?

Tip: When applying the quotient rule, always check for cases where the denominator is zero, as this could indicate an undefined point or require careful handling to avoid division by zero.

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Math Problem Analysis

Mathematical Concepts

Calculus
Quotient Rule
Derivative
Graph Analysis

Formulas

Quotient Rule: h'(x) = (f'(x)g(x) - f(x)g'(x)) / [g(x)]^2

Theorems

Quotient Rule

Suitable Grade Level

College Calculus or Advanced High School Calculus