Math Problem Statement

Suppose f and g are two differentiable functions. Some values of f(x), f 0 (x), g(x) and g 0 (x) (for x = 2, 3, 5) are given in the table below. x f(x) f 0 (x) g(x) g 0 (x) 2 10 −1 5 3 3 1 2 5 7 5 −3 4 −2 4 If h = f ◦ g is the composition h(x) = f(g(x)), what is the value of h 0 (3)?

Solution

To find the value of h(3)h'(3), where h(x)=f(g(x))h(x) = f(g(x)), we need to use the chain rule for differentiation. The chain rule states that if h(x)=f(g(x))h(x) = f(g(x)), then:

h(x)=f(g(x))g(x)h'(x) = f'(g(x)) \cdot g'(x)

To determine h(3)h'(3), we substitute x=3x = 3:

h(3)=f(g(3))g(3)h'(3) = f'(g(3)) \cdot g'(3)

From the table, we have the following values:

  • g(3)=5g(3) = 5
  • g(3)=7g'(3) = 7

Now, we need f(g(3))=f(5)f'(g(3)) = f'(5). From the table, f(5)=4f'(5) = 4.

Now, substitute these values into the expression for h(3)h'(3):

h(3)=f(5)g(3)=47=28h'(3) = f'(5) \cdot g'(3) = 4 \cdot 7 = 28

Therefore, the value of h(3)h'(3) is:

h(3)=28h'(3) = 28

Would you like additional details or have questions?

Here are some related questions to explore further:

  1. How does the chain rule apply to other compositions, like k(x)=g(f(x))k(x) = g(f(x))?
  2. What changes if the functions ff and gg were not differentiable?
  3. How would you interpret h(x)=f(g(x))h(x) = f(g(x)) graphically?
  4. What if g(x)g(x) were a constant function? How would h(x)h'(x) behave?
  5. Can the chain rule be extended to compositions involving more than two functions?

Tip: For compositions, always differentiate the outer function evaluated at the inner function times the derivative of the inner function.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Chain Rule
Function Composition

Formulas

h'(x) = f'(g(x)) * g'(x)

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12