Math Problem Statement

Find the area bounded by the graphs of the indicated equations over the given interval.

yequals=e Superscript 0.75 xe0.75x​;

yequals=negative StartFraction 1 Over x EndFraction−1x​;

1 less than or equals x less than or equals 21≤x≤2

Question content area bottom

Part 1

The area is

enter your response here

square units.

​(Type an integer or decimal rounded to three decimal places as​ needed.)

Solution

To find the area bounded by the graphs of the two equations y=e0.75xy = e^{0.75x} and y=1xy = -\frac{1}{x} over the interval 1x21 \leq x \leq 2, we need to follow these steps:

Step 1: Set up the integral

The area between two curves is given by the formula: A=ab(f(x)g(x))dxA = \int_{a}^{b} \left( f(x) - g(x) \right) \, dx where f(x)f(x) is the upper function and g(x)g(x) is the lower function over the interval [a,b][a, b].

From the problem:

  • The function f(x)=e0.75xf(x) = e^{0.75x}
  • The function g(x)=1xg(x) = -\frac{1}{x}

We are given the interval 1x21 \leq x \leq 2.

Step 2: Identify the upper and lower functions

To find out which function is on top, we need to evaluate both functions at a few points within the interval:

  • At x=1x = 1: e0.75(1)=e0.752.117e^{0.75(1)} = e^{0.75} \approx 2.117 11=1-\frac{1}{1} = -1 So, e0.75xe^{0.75x} is greater than 1x-\frac{1}{x} at x=1x = 1.

  • At x=2x = 2: e0.75(2)=e1.54.4817e^{0.75(2)} = e^{1.5} \approx 4.4817 12=0.5-\frac{1}{2} = -0.5 So, e0.75xe^{0.75x} is also greater than 1x-\frac{1}{x} at x=2x = 2.

Thus, the function f(x)=e0.75xf(x) = e^{0.75x} is the upper function, and g(x)=1xg(x) = -\frac{1}{x} is the lower function.

Step 3: Set up the integral

Now we set up the integral for the area between the curves: A=12(e0.75x(1x))dxA = \int_{1}^{2} \left( e^{0.75x} - \left( -\frac{1}{x} \right) \right) \, dx which simplifies to: A=12(e0.75x+1x)dxA = \int_{1}^{2} \left( e^{0.75x} + \frac{1}{x} \right) \, dx

Step 4: Compute the integral

We need to compute the integral of both terms separately:

  1. The integral of e0.75xe^{0.75x} is: e0.75xdx=10.75e0.75x=43e0.75x\int e^{0.75x} \, dx = \frac{1}{0.75} e^{0.75x} = \frac{4}{3} e^{0.75x}
  2. The integral of 1x\frac{1}{x} is: 1xdx=lnx\int \frac{1}{x} \, dx = \ln|x|

Now, we apply the limits of integration from 1 to 2.

A=[43e0.75x+lnx]12A = \left[ \frac{4}{3} e^{0.75x} + \ln|x| \right]_{1}^{2} Substitute the upper limit x=2x = 2 and the lower limit x=1x = 1:

A=(43e0.75(2)+ln(2))(43e0.75(1)+ln(1))A = \left( \frac{4}{3} e^{0.75(2)} + \ln(2) \right) - \left( \frac{4}{3} e^{0.75(1)} + \ln(1) \right) Since ln(1)=0\ln(1) = 0, this simplifies to: A=(43e1.5+ln(2))43e0.75A = \left( \frac{4}{3} e^{1.5} + \ln(2) \right) - \frac{4}{3} e^{0.75}

Now let's compute this numerically:

A(43×4.4817+0.6931)43×2.117A \approx \left( \frac{4}{3} \times 4.4817 + 0.6931 \right) - \frac{4}{3} \times 2.117

A(5.9756+0.6931)2.8227A \approx \left( 5.9756 + 0.6931 \right) - 2.8227

A6.66872.8227=3.846A \approx 6.6687 - 2.8227 = 3.846

Final Answer:

The area is approximately 3.8463.846 square units.

Let me know if you want further details or have any questions!

Here are 5 questions related to this:

  1. How would you interpret the area between curves geometrically?
  2. What would change if the interval was 1x31 \leq x \leq 3?
  3. How does the exponential growth of e0.75xe^{0.75x} affect the area?
  4. Can we find the exact intersection point of the two curves?
  5. How do we handle areas when curves cross over each other?

Tip: When calculating the area between curves, always make sure you correctly identify which curve is on top!

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Math Problem Analysis

Mathematical Concepts

Integral Calculus
Area Between Curves
Exponential Functions
Rational Functions

Formulas

A = ∫[a to b] (f(x) - g(x)) dx
Integral of e^(kx) = (1/k)e^(kx)
Integral of 1/x = ln|x|

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

College Level Calculus