Math Problem Statement

Evaluate f'(3), f'(6), g'(3), g'(6), and determine where g(x) has local maximum and minimum in the interval (0, 6).

Solution

Let's analyze and solve the given problem step by step. Here’s the process:


The graph of f(x)f(x):

  • It consists of line segments, a semicircle, and another set of line segments.
  • g(x)g(x) is defined as: g(x)=0xf(t)dtg(x) = \int_0^x f(t) \, dt This means g(x)=f(x)g'(x) = f(x), by the Fundamental Theorem of Calculus.

Question (b): Evaluate f(3)f'(3) and f(6)f'(6):

  • f(3)f'(3): At x=3x = 3, the graph shows a change in direction of the semicircle. f(3)f'(3) is undefined because f(x)f(x) is not smooth (it has a cusp at x=3x = 3).

  • f(6)f'(6): At x=6x = 6, the graph of f(x)f(x) is a horizontal line, meaning f(6)=0f'(6) = 0.


Question (c): Evaluate g(3)g'(3) and g(6)g'(6):

  • Since g(x)=f(x)g'(x) = f(x), we simply evaluate f(x)f(x) at x=3x = 3 and x=6x = 6:
    • g(3)=f(3)g'(3) = f(3): From the graph, f(3)=1f(3) = -1.
    • g(6)=f(6)g'(6) = f(6): From the graph, f(6)=0f(6) = 0.

Question (d): Local maximum of g(x)g(x) on (0,6)(0, 6):

  • For g(x)g(x) to have a local maximum, g(x)=f(x)g'(x) = f(x) must change sign from positive to negative.
  • From the graph, f(x)f(x) changes from positive to negative at x=2x = 2, so g(x)g(x) has a local maximum at x=2x = 2.

Question (e): Local minimum of g(x)g(x) on (0,6)(0, 6):

  • For g(x)g(x) to have a local minimum, g(x)=f(x)g'(x) = f(x) must change sign from negative to positive.
  • From the graph, f(x)f(x) changes from negative to positive at x=4x = 4, so g(x)g(x) has a local minimum at x=4x = 4.

Final Answers:

(b)
f(3)=undefined, f(6)=0f'(3) = \text{undefined}, \ f'(6) = 0

(c)
g(3)=1, g(6)=0g'(3) = -1, \ g'(6) = 0

(d)
Local maximum of g(x)g(x) occurs at x=2x = 2.

(e)
Local minimum of g(x)g(x) occurs at x=4x = 4.


Would you like me to elaborate on any part of this solution? Here are five related questions for deeper understanding:

  1. Why is f(3)f'(3) undefined at x=3x = 3, and how do cusps affect derivatives?
  2. How does the Fundamental Theorem of Calculus relate g(x)g(x) and f(x)f(x)?
  3. What are the conditions for local extrema in integrals of functions?
  4. Can g(x)g(x) have a local extremum at a point where f(x)f(x) is undefined?
  5. How does the semicircle segment contribute to the behavior of g(x)g(x)?

Tip: For interpreting problems involving g(x)=0xf(t)dtg(x) = \int_0^x f(t) \, dt, always start by analyzing the graph of f(x)f(x) for critical points and changes in sign.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Integrals
Fundamental Theorem of Calculus
Local Extrema

Formulas

g(x) = ∫_0^x f(t) dt
g'(x) = f(x)

Theorems

Fundamental Theorem of Calculus
Conditions for local extrema

Suitable Grade Level

Grades 11-12