Math Problem Statement

Find derivatives using product rule and quotient rule, and solve for when f'(x) = h'(x).

Solution

Let's go through the problems step by step from this worksheet.


a. The function k(x)k(x) is defined by k(x)=f(x)g(x)k(x) = f(x)g(x). Find k(0)k'(0). (3 points)

To find k(x)k'(x), we use the product rule: k(x)=f(x)g(x)+f(x)g(x).k'(x) = f'(x)g(x) + f(x)g'(x).

We are asked to find k(0)k'(0), so: k(0)=f(0)g(0)+f(0)g(0).k'(0) = f'(0)g(0) + f(0)g'(0).

From the graph of f(x)f(x), we can estimate f(0)f(0), f(0)f'(0), and then we need to know g(0)g(0) and g(0)g'(0).

Based on the graph and given functions, you can:

  1. Evaluate f(0)f(0) from the graph directly.
  2. Use g(x)=x2x+3g(x) = \sqrt{x^2 - x + 3} to find g(0)g(0) and g(0)g'(0).

Once you have these values, you can plug them into the product rule expression to get k(0)k'(0).


b. The function m(x)m(x) is defined by m(x)=f(x)2g(x)m(x) = \frac{f(x)}{2g(x)}. Find m(5)m'(5). (3 points)

To differentiate this function, we'll apply the quotient rule: m(x)=f(x)2g(x)f(x)2g(x)(2g(x))2.m'(x) = \frac{f'(x) \cdot 2g(x) - f(x) \cdot 2g'(x)}{(2g(x))^2}.

We are asked to find m(5)m'(5), so: m(5)=f(5)2g(5)f(5)2g(5)(2g(5))2.m'(5) = \frac{f'(5) \cdot 2g(5) - f(5) \cdot 2g'(5)}{(2g(5))^2}.

Steps:

  1. Find f(5)f(5) and f(5)f'(5) from the graph.
  2. Use the expression for g(x)=x2x+3g(x) = \sqrt{x^2 - x + 3} to find g(5)g(5) and g(5)g'(5).

Plug these values into the quotient rule formula to get m(5)m'(5).


c. Find the value of xx for 1<x<2-1 < x < 2 such that f(x)=h(x)f'(x) = h'(x). (2 points)

We are looking for the value of xx where the derivatives of f(x)f(x) and h(x)h(x) are equal.

Steps:

  1. Use the graph to find f(x)f'(x) in the interval 1<x<2-1 < x < 2.
  2. Use the derivative of h(x)=5ex9sin(x)h(x) = 5e^x - 9\sin(x), which is: h(x)=5ex9cos(x).h'(x) = 5e^x - 9\cos(x).
  3. Set f(x)=h(x)f'(x) = h'(x) and solve for xx in the given interval.

Would you like to go deeper into any of these parts?

Here are five related follow-up questions:

  1. How is the product rule applied to more complex combinations of functions?
  2. Can you explain the steps in applying the quotient rule to rational functions?
  3. How do we estimate derivative values using graphs?
  4. How do we solve transcendental equations, like f(x)=h(x)f'(x) = h'(x), involving both exponentials and trigonometric functions?
  5. What is the significance of understanding both local behavior (derivatives) and global behavior of functions?

Tip: When solving problems involving graphs, make sure to carefully analyze the slope (derivative) at key points to accurately find values like f(x)f'(x).

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Math Problem Analysis

Mathematical Concepts

Differentiation
Product Rule
Quotient Rule
Graph Analysis

Formulas

Product Rule: k'(x) = f'(x)g(x) + f(x)g'(x)
Quotient Rule: m'(x) = (f'(x)2g(x) - f(x)2g'(x)) / (2g(x))^2
Derivative of h(x) = 5e^x - 9sin(x): h'(x) = 5e^x - 9cos(x)

Theorems

Product Rule
Quotient Rule

Suitable Grade Level

Grades 10-12