Math Problem Statement

integrate1/1+sinx with respect to x with upper limit pi/2 and lower limit 0 using Simpson's rule with six strips

Solution

To integrate 11+sinx\frac{1}{1 + \sin x} with respect to xx using Simpson's rule with six strips over the interval [0,π2][0, \frac{\pi}{2}], follow these steps:

  1. Determine the width of each strip: The interval is [0,π2][0, \frac{\pi}{2}] and we are using six strips. Thus, the width hh of each strip is: h=π206=π12h = \frac{\frac{\pi}{2} - 0}{6} = \frac{\pi}{12}

  2. Calculate the xx-values: The xx-values at the endpoints of each strip are: x0=0,x1=π12,x2=π6,x3=π4,x4=5π12,x5=π2,x6=π2x_0 = 0, \quad x_1 = \frac{\pi}{12}, \quad x_2 = \frac{\pi}{6}, \quad x_3 = \frac{\pi}{4}, \quad x_4 = \frac{5\pi}{12}, \quad x_5 = \frac{\pi}{2}, \quad x_6 = \frac{\pi}{2}

  3. Evaluate the function at these points: Calculate the function values at these points: f(x)=11+sinxf(x) = \frac{1}{1 + \sin x} f(x0)=11+sin0=1f(x_0) = \frac{1}{1 + \sin 0} = 1 f(x1)=11+sin(π12)f(x_1) = \frac{1}{1 + \sin \left(\frac{\pi}{12}\right)} f(x2)=11+sin(π6)=11+12=23f(x_2) = \frac{1}{1 + \sin \left(\frac{\pi}{6}\right)} = \frac{1}{1 + \frac{1}{2}} = \frac{2}{3} f(x3)=11+sin(π4)=11+22=22+2f(x_3) = \frac{1}{1 + \sin \left(\frac{\pi}{4}\right)} = \frac{1}{1 + \frac{\sqrt{2}}{2}} = \frac{2}{2 + \sqrt{2}} f(x4)=11+sin(5π12)f(x_4) = \frac{1}{1 + \sin \left(\frac{5\pi}{12}\right)} f(x5)=11+sin(π2)=12f(x_5) = \frac{1}{1 + \sin \left(\frac{\pi}{2}\right)} = \frac{1}{2} f(x6)=11+sin(π2)=12f(x_6) = \frac{1}{1 + \sin \left(\frac{\pi}{2}\right)} = \frac{1}{2}

  4. Apply Simpson's rule: Simpson's rule is given by: abf(x)dxh3[f(x0)+4f(x1)+2f(x2)+4f(x3)+2f(x4)+4f(x5)+f(x6)]\int_{a}^{b} f(x) \, dx \approx \frac{h}{3} \left[f(x_0) + 4f(x_1) + 2f(x_2) + 4f(x_3) + 2f(x_4) + 4f(x_5) + f(x_6)\right]

    Plugging in the values: 0π211+sinxdxπ123[1+4f(x1)+223+422+2+2f(x4)+412+12]\int_{0}^{\frac{\pi}{2}} \frac{1}{1 + \sin x} \, dx \approx \frac{\frac{\pi}{12}}{3} \left[1 + 4f(x_1) + 2 \cdot \frac{2}{3} + 4 \cdot \frac{2}{2 + \sqrt{2}} + 2f(x_4) + 4 \cdot \frac{1}{2} + \frac{1}{2}\right]

    Simplifying the coefficients: =π36[1+4f(x1)+43+82+2+2f(x4)+2+12]= \frac{\pi}{36} \left[1 + 4f(x_1) + \frac{4}{3} + \frac{8}{2 + \sqrt{2}} + 2f(x_4) + 2 + \frac{1}{2}\right]

  5. Complete the evaluation: Substitute f(x1)f(x_1) and f(x4)f(x_4) with their values (or numerically compute): f(x1)0.927andf(x4)0.737f(x_1) \approx 0.927 \quad \text{and} \quad f(x_4) \approx 0.737

    Hence: =π36[1+40.927+43+82+2+20.737+2+12]= \frac{\pi}{36} \left[1 + 4 \cdot 0.927 + \frac{4}{3} + \frac{8}{2 + \sqrt{2}} + 2 \cdot 0.737 + 2 + \frac{1}{2}\right]

    =π36[1+3.708+1.333+82+2+1.474+2+0.5]= \frac{\pi}{36} \left[1 + 3.708 + 1.333 + \frac{8}{2 + \sqrt{2}} + 1.474 + 2 + 0.5\right]

    =π36[1+3.708+1.333+1.860+1.474+2+0.5]= \frac{\pi}{36} \left[1 + 3.708 + 1.333 + 1.860 + 1.474 + 2 + 0.5\right]

    =π36[11.875]= \frac{\pi}{36} \left[11.875\right]

    =11.875π36= \frac{11.875 \pi}{36}

Therefore, the approximate value of the integral using Simpson's rule with six strips is: 0π211+sinxdx1.036\int_{0}^{\frac{\pi}{2}} \frac{1}{1 + \sin x} \, dx \approx 1.036

Would you like more details or have any questions? Here are 5 other questions you might find interesting:

  1. How to find the Taylor series expansion of a function?
  2. What is the divergence theorem and how is it used in vector calculus?
  3. How to solve a differential equation using the method of undetermined coefficients?
  4. Can you explain the concept of eigenvalues and eigenvectors?
  5. How to perform polynomial long division?

Tip: When using numerical methods like Simpson's rule, ensure that the function values are accurately computed to maintain precision in the final result.

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Math Problem Analysis

Mathematical Concepts

Integration
Numerical Methods
Simpson's Rule

Formulas

Simpson's rule

Theorems

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Suitable Grade Level

Advanced College Level