Math Problem Statement

Find the area between y = 2 and y = cos x + 1 for 0 ≤ x ≤ 2π

Solution

To find the area between the curves y=2y = 2 and y=cosx+1y = \cos x + 1 over the interval 0x2π0 \leq x \leq 2\pi, we calculate the definite integral of the difference between the two functions over that interval.

Step 1: Set Up the Integral

The area AA between the curves is given by:

A=02π[2(cosx+1)]dxA = \int_{0}^{2\pi} \left[2 - (\cos x + 1)\right] \, dx

Step 2: Simplify the Integrand

Simplifying the expression inside the integral:

A=02π[2cosx1]dx=02π(1cosx)dxA = \int_{0}^{2\pi} \left[2 - \cos x - 1\right] \, dx = \int_{0}^{2\pi} \left(1 - \cos x\right) \, dx

Step 3: Integrate

Now, integrate the simplified expression:

A=02π1dx02πcosxdxA = \int_{0}^{2\pi} 1 \, dx - \int_{0}^{2\pi} \cos x \, dx

  1. The first integral is straightforward: 02π1dx=x02π=2π\int_{0}^{2\pi} 1 \, dx = \left. x \right|_{0}^{2\pi} = 2\pi

  2. The second integral is: 02πcosxdx=sinx02π=sin(2π)sin(0)=00=0\int_{0}^{2\pi} \cos x \, dx = \left. \sin x \right|_{0}^{2\pi} = \sin(2\pi) - \sin(0) = 0 - 0 = 0

Step 4: Calculate the Area

Subtract the results of the two integrals:

A=2π0=2πA = 2\pi - 0 = 2\pi

Final Answer

The area between the curves y=2y = 2 and y=cosx+1y = \cos x + 1 from 0x2π0 \leq x \leq 2\pi is 2π2\pi square units.

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

Here are some related questions to explore:

  1. How would the area change if the interval was 0xπ0 \leq x \leq \pi?
  2. What is the area between the curves y=cosx+1y = \cos x + 1 and y=1y = 1 over the same interval?
  3. How would you find the area between y=cosx+1y = \cos x + 1 and y=cosx+1y = -\cos x + 1?
  4. What happens to the area if you shift the curve y=cosx+1y = \cos x + 1 vertically by 1 unit?
  5. How would the integration limits change if the region were confined to y=1.5y = 1.5?

Tip: When dealing with areas between curves, always ensure the integrand represents the correct difference between the upper and lower functions.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integrals
Area Between Curves

Formulas

Definite integral formula

Theorems

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Suitable Grade Level

Advanced High School