Math Problem Statement

The graph of the function f, consisting of two line segments, is shown in the figure above. Let g be the function given by g(x) = 2x + 1, and let h be the function given by h(x) = f(g(x)). What is the value of h'(1)?

Solution

We are tasked with finding h(1)h'(1), where h(x)=f(g(x))h(x) = f(g(x)). This is the composition of two functions: g(x)=2x+1g(x) = 2x + 1 and the piecewise linear function f(x)f(x) as shown in the graph.

Step 1: Differentiate h(x)=f(g(x))h(x) = f(g(x))

By the chain rule, we know that: h(x)=f(g(x))g(x)h'(x) = f'(g(x)) \cdot g'(x) where g(x)g'(x) is the derivative of g(x)g(x), and f(x)f'(x) is the derivative of f(x)f(x).

Step 2: Calculate g(x)g'(x)

The function g(x)=2x+1g(x) = 2x + 1 is linear, so: g(x)=2g'(x) = 2

Step 3: Evaluate g(1)g(1)

Substitute x=1x = 1 into g(x)g(x): g(1)=2(1)+1=3g(1) = 2(1) + 1 = 3 Thus, g(1)=3g(1) = 3, so we need to evaluate f(3)f'(3).

Step 4: Determine f(3)f'(3)

Now, let's look at the graph of f(x)f(x). The graph consists of two line segments:

  • From (0,0)(0, 0) to (1,4)(1, 4)
  • From (1,4)(1, 4) to (4,2)(4, -2)

The slope of the segment from (1,4)(1, 4) to (4,2)(4, -2) is: slope of f(x) on this segment=2441=63=2\text{slope of } f(x) \text{ on this segment} = \frac{-2 - 4}{4 - 1} = \frac{-6}{3} = -2 Since 33 lies on this second segment, we conclude that f(3)=2f'(3) = -2.

Step 5: Calculate h(1)h'(1)

Now apply the chain rule: h(1)=f(g(1))g(1)=f(3)2=(2)2=4h'(1) = f'(g(1)) \cdot g'(1) = f'(3) \cdot 2 = (-2) \cdot 2 = -4

Thus, the value of h(1)h'(1) is 4\boxed{-4}.

Would you like more details on any part of the explanation?

Related questions:

  1. What is the geometric meaning of f(x)f'(x) in this context?
  2. How does the chain rule work for function compositions?
  3. What are other examples where a piecewise function is involved in differentiation?
  4. Can we explore other values of h(x)h'(x) for different points besides x=1x = 1?
  5. How does the slope of a line segment impact the derivative of a function?

Tip:

Always check the graph of a piecewise linear function carefully to identify the correct slope (derivative) for the relevant interval.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Function Composition
Piecewise Linear Functions
Differentiation
Chain Rule

Formulas

h'(x) = f'(g(x)) * g'(x)
g(x) = 2x + 1

Theorems

Chain Rule for Differentiation

Suitable Grade Level

Grades 10-12