Math Problem Statement

Let k(x) = (f(x)g(x)) / h(x). If f(-3) = -1, f'(-3) = -5, g(-3) = 8, g'(-3) = 5, h(-3) = -2, and h'(-3) = -8, what is k'(-3)?

Solution

We are given the function k(x)=f(x)g(x)h(x)k(x) = \frac{f(x)g(x)}{h(x)}, and we need to find k(3)k'(-3). To do this, we will apply the quotient rule for differentiation.

Step 1: Quotient Rule

The derivative of k(x)=f(x)g(x)h(x)k(x) = \frac{f(x)g(x)}{h(x)} is given by the quotient rule: k(x)=(f(x)g(x)+f(x)g(x))h(x)f(x)g(x)h(x)(h(x))2k'(x) = \frac{(f'(x)g(x) + f(x)g'(x))h(x) - f(x)g(x)h'(x)}{(h(x))^2} Now, substitute x=3x = -3 and use the given values:

  • f(3)=1f(-3) = -1
  • f(3)=5f'(-3) = -5
  • g(3)=8g(-3) = 8
  • g(3)=5g'(-3) = 5
  • h(3)=2h(-3) = -2
  • h(3)=8h'(-3) = -8

Step 2: Plug in the values into the derivative formula

Substitute the given values into the formula for k(3)k'(-3): k(3)=(f(3)g(3)+f(3)g(3))h(3)f(3)g(3)h(3)(h(3))2k'(-3) = \frac{(f'(-3)g(-3) + f(-3)g'(-3))h(-3) - f(-3)g(-3)h'(-3)}{(h(-3))^2} Substitute the specific values: k(3)=((5)(8)+(1)(5))(2)(1)(8)(8)(2)2k'(-3) = \frac{((-5)(8) + (-1)(5))(-2) - (-1)(8)(-8)}{(-2)^2}

Step 3: Simplify the expression

First, simplify the terms inside the numerator: k(3)=((40)+(5))(2)(8)(8)4k'(-3) = \frac{((-40) + (-5))(-2) - (8)(8)}{4} k(3)=(45)(2)644k'(-3) = \frac{(-45)(-2) - 64}{4} k(3)=90644k'(-3) = \frac{90 - 64}{4} k(3)=264=6.5k'(-3) = \frac{26}{4} = 6.5

Thus, k(3)=6.5k'(-3) = 6.5.

Let me know if you need further details or clarifications! Would you like me to expand on any part of the process?

Here are 5 related questions for further practice:

  1. How do you apply the product rule in combination with the quotient rule?
  2. How would the result change if h(3)h'(-3) had a different value?
  3. What happens if h(x)h(x) is 0 at some point in the domain of k(x)k(x)?
  4. How would you differentiate if k(x)=f(x)g(x)k(x) = \frac{f(x)}{g(x)}?
  5. How does the chain rule factor into more complex quotient rule problems?

Tip: When applying the quotient rule, be careful to apply it in the correct order, ensuring the subtraction in the numerator is maintained properly.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Quotient Rule

Formulas

Quotient Rule: (u / v)' = (u'v - uv') / v^2
Derivative of k(x) = (f(x)g(x)) / h(x): k'(x) = [(f'(x)g(x) + f(x)g'(x))h(x) - f(x)g(x)h'(x)] / (h(x))^2

Theorems

Quotient Rule

Suitable Grade Level

Grades 11-12 / College Calculus