Math Problem Statement

Find the value or values of c that satisfy the equation f(b) - f(a) / (b - a) = f'(c) in the conclusion of the Mean Value Theorem for the given function and interval. f(x) = 7x + 7/x on the interval [1/10, 10].

Solution

The problem asks to find the value or values of cc that satisfy the equation

f(b)f(a)ba=f(c)\frac{f(b) - f(a)}{b - a} = f'(c)

for the given function and interval, using the Mean Value Theorem (MVT).

Step 1: Analyze the Given Function and Interval

The function is: f(x)=7x+7xf(x) = 7x + \frac{7}{x} And the interval is [110,10]\left[\frac{1}{10}, 10\right].

Step 2: Mean Value Theorem

According to the Mean Value Theorem, there exists at least one value cc in the open interval (110,10)\left( \frac{1}{10}, 10 \right) such that:

f(c)=f(10)f(110)10110f'(c) = \frac{f(10) - f\left(\frac{1}{10}\right)}{10 - \frac{1}{10}}

Step 3: Compute f(x)f'(x)

To apply the MVT, we first need the derivative f(x)f'(x).

f(x)=7x+7xf(x) = 7x + \frac{7}{x} Using the power rule and the chain rule, we differentiate:

f(x)=77x2f'(x) = 7 - \frac{7}{x^2}

Step 4: Calculate f(10)f(10) and f(110)f\left(\frac{1}{10}\right)

  • f(10)=7(10)+710=70+0.7=70.7f(10) = 7(10) + \frac{7}{10} = 70 + 0.7 = 70.7
  • f(110)=7(110)+7110=0.7+70=70.7f\left(\frac{1}{10}\right) = 7\left(\frac{1}{10}\right) + \frac{7}{\frac{1}{10}} = 0.7 + 70 = 70.7

Step 5: Compute the Difference Quotient

Now calculate:

f(10)f(110)10110=70.770.7100.1=09.9=0\frac{f(10) - f\left(\frac{1}{10}\right)}{10 - \frac{1}{10}} = \frac{70.7 - 70.7}{10 - 0.1} = \frac{0}{9.9} = 0

Thus, the right-hand side of the Mean Value Theorem equation is 00.

Step 6: Set f(c)=0f'(c) = 0

From the MVT, we now have:

77c2=07 - \frac{7}{c^2} = 0

Solve for cc:

7=7c27 = \frac{7}{c^2}

c2=1c^2 = 1

c=±1c = \pm 1

Step 7: Check If cc Lies in the Interval

The interval is (110,10)\left(\frac{1}{10}, 10\right). So, c=1c = 1 is the only valid solution because c=1c = -1 is not in the interval.

Final Answer:

The value of cc that satisfies the Mean Value Theorem is:

c=1c = 1


Would you like more details or have any other questions?

Here are 5 relative questions for further exploration:

  1. What happens if the function was different, such as f(x)=x3f(x) = x^3?
  2. How would the problem change if the interval were [2,5][2, 5]?
  3. Why does the MVT require a differentiable function on an open interval?
  4. How is the Mean Value Theorem applied in real-world scenarios?
  5. What is the difference between the Mean Value Theorem and Rolle's Theorem?

Tip: The Mean Value Theorem guarantees at least one value cc, but in some cases, multiple cc-values might satisfy the equation depending on the function's behavior.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Mean Value Theorem

Formulas

f(b) - f(a) / (b - a) = f'(c)
f'(x) = 7 - 7/x^2

Theorems

Mean Value Theorem

Suitable Grade Level

Undergraduate Calculus