Math Problem Statement

Find the area bounded by the graphs of the equations y = e^x and y = -1/x over the interval 1 ≤ x ≤ 2.

Solution

To solve the problem of finding the area bounded by the given equations y=exy = e^x and y=1xy = -\frac{1}{x} over the interval 1x21 \leq x \leq 2, we proceed as follows:

  1. Find the points of intersection (if necessary): For y=exy = e^x and y=1xy = -\frac{1}{x}, we check if they intersect in the given interval 1x21 \leq x \leq 2. However, in this case, we are simply calculating the bounded area between the two curves over the interval, so intersection points are not required here.

  2. Set up the integral:
    The upper function is y=exy = e^x, and the lower function is y=1xy = -\frac{1}{x}. The area AA is given by: A=12(ex(1x))dx=12(ex+1x)dx.A = \int_1^2 \left(e^x - \left(-\frac{1}{x}\right)\right) dx = \int_1^2 \left(e^x + \frac{1}{x}\right) dx.

  3. Evaluate the integral: Break it into two parts: A=12exdx+121xdx.A = \int_1^2 e^x dx + \int_1^2 \frac{1}{x} dx.

    • The first integral: exdx=exevaluated from 1 to 2.\int e^x dx = e^x \quad \text{evaluated from 1 to 2.} This becomes: e2e1.e^2 - e^1.

    • The second integral: 1xdx=lnxevaluated from 1 to 2.\int \frac{1}{x} dx = \ln|x| \quad \text{evaluated from 1 to 2.} This becomes: ln(2)ln(1).\ln(2) - \ln(1). Since ln(1)=0\ln(1) = 0, this simplifies to ln(2)\ln(2).

  4. Combine the results: Add the results of both integrals: A=(e2e1)+ln(2).A = (e^2 - e^1) + \ln(2). Simplify: A=e2e+ln(2).A = e^2 - e + \ln(2).

Thus, the bounded area is A=e2e+ln(2)A = e^2 - e + \ln(2).

Let me know if you would like me to provide further clarification, a numerical approximation of the result, or visualize the bounded region.

Here are 5 related questions you may find helpful:

  1. How do you graphically verify the bounded area between two curves?
  2. What is the difference between definite and indefinite integration?
  3. How does the choice of interval affect the bounded area calculation?
  4. How is the natural exponential function exe^x important in calculus?
  5. How does logarithmic integration apply to real-world problems?

Tip: Always ensure the correct order of subtraction (upper function minus lower function) when setting up the integral for bounded areas.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Definite Integration
Area between Curves
Exponential and Logarithmic Functions

Formulas

Area = ∫[a, b] (f(x) - g(x)) dx
∫ e^x dx = e^x + C
∫ 1/x dx = ln|x| + C

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12 or early college