Math Problem Statement

Let u(x) = f(x)g(x) and v(x) = f(x)/g(x). Find u'(1) and v'(5) based on the graphs of functions f and g.

Solution

Let's analyze and solve each part of this problem based on the given information.

  1. Identifying u(x)=f(x)g(x)u(x) = f(x) \cdot g(x) and finding u(x)u'(x): Since u(x)=f(x)g(x)u(x) = f(x) \cdot g(x), we use the product rule to find u(x)u'(x): u(x)=f(x)g(x)+f(x)g(x)u'(x) = f'(x) \cdot g(x) + f(x) \cdot g'(x) For u(1)u'(1), we need the values of f(1)f(1), g(1)g(1), f(1)f'(1), and g(1)g'(1) from the graph.

  2. Identifying v(x)=f(x)g(x)v(x) = \frac{f(x)}{g(x)} and finding v(x)v'(x): Since v(x)=f(x)g(x)v(x) = \frac{f(x)}{g(x)}, we use the quotient rule to find v(x)v'(x): v(x)=f(x)g(x)f(x)g(x)[g(x)]2v'(x) = \frac{f'(x) \cdot g(x) - f(x) \cdot g'(x)}{[g(x)]^2} For v(5)v'(5), we need the values of f(5)f(5), g(5)g(5), f(5)f'(5), and g(5)g'(5) from the graph.

Step-by-Step Solutions

(a) Find u(1)u'(1):

From the graph:

  • f(1)=3f(1) = 3
  • g(1)=1g(1) = 1
  • f(1)f'(1): The slope of f(x)f(x) at x=1x = 1 is the slope of the line segment around x=1x = 1, which appears to be 1-1.
  • g(1)g'(1): The slope of g(x)g(x) at x=1x = 1 is also calculated from the slope of the segment, which appears to be 22.

Now, plug these values into the formula for u(x)u'(x): u(1)=f(1)g(1)+f(1)g(1)=(1)1+32=1+6=5u'(1) = f'(1) \cdot g(1) + f(1) \cdot g'(1) = (-1) \cdot 1 + 3 \cdot 2 = -1 + 6 = 5 So, u(1)=5u'(1) = 5.

(b) Find v(5)v'(5):

From the graph:

  • f(5)=2f(5) = 2
  • g(5)=3g(5) = 3
  • f(5)f'(5): The slope of f(x)f(x) at x=5x = 5 is calculated from the nearby segment, which appears to be 1-1.
  • g(5)g'(5): The slope of g(x)g(x) at x=5x = 5 is also calculated from the segment, which appears to be 11.

Now, plug these values into the formula for v(x)v'(x): v(5)=f(5)g(5)f(5)g(5)[g(5)]2=(1)32132=329=59v'(5) = \frac{f'(5) \cdot g(5) - f(5) \cdot g'(5)}{[g(5)]^2} = \frac{(-1) \cdot 3 - 2 \cdot 1}{3^2} = \frac{-3 - 2}{9} = \frac{-5}{9} So, v(5)=59v'(5) = -\frac{5}{9}.

Answers

  • (a) u(1)=5u'(1) = 5
  • (b) v(5)=59v'(5) = -\frac{5}{9}

Would you like more details, or have questions on any step?

Additional Related Questions:

  1. How would the result change if f(x)f(x) or g(x)g(x) had a different slope at x=1x = 1?
  2. What if we needed to find u(x)u'(x) for another value, such as x=2x = 2?
  3. How would the derivative change if u(x)u(x) were defined as f(x)+g(x)f(x) + g(x) instead of f(x)g(x)f(x) \cdot g(x)?
  4. What are the implications if g(x)g(x) had a value of zero at x=1x = 1?
  5. Could we find v(x)v'(x) if g(x)g(x) were zero at x=5x = 5? What would happen?

Tip:

Always verify the slopes (derivatives) carefully by calculating the rise-over-run for each segment on the graph; it ensures precise differentiation.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivative
Product Rule
Quotient Rule

Formulas

u'(x) = f'(x)g(x) + f(x)g'(x)
v'(x) = (f'(x)g(x) - f(x)g'(x)) / [g(x)]^2

Theorems

Product Rule
Quotient Rule

Suitable Grade Level

Grades 11-12 or introductory calculus courses