Math Problem Statement

sin(t)/t using simpsons rule and n=4

Solution

To approximate the integral of sin(t)t\frac{\sin(t)}{t} using Simpson's Rule with n=4n = 4, we'll first need to recall the general formula for Simpson's Rule:

abf(x)dxh3[f(x0)+4i=1,3,5,...,n1f(xi)+2i=2,4,6,...,n2f(xi)+f(xn)]\int_a^b f(x) \, dx \approx \frac{h}{3} \left[ f(x_0) + 4 \sum_{i=1,3,5,...,n-1} f(x_i) + 2 \sum_{i=2,4,6,...,n-2} f(x_i) + f(x_n) \right]

Where:

  • h=banh = \frac{b - a}{n} is the step size.
  • nn is the number of intervals (which is even).
  • x0,x1,x2,,xnx_0, x_1, x_2, \dots, x_n are the points on the interval [a,b][a, b].

Let's assume you want to integrate sin(t)t\frac{\sin(t)}{t} over the interval [a,b][a, b]. For simplicity, let's take the standard interval [0,1][0, 1]. We need to use Simpson's Rule for this integral.

  1. Define the function: f(t)=sin(t)tf(t) = \frac{\sin(t)}{t}. Note that we must handle t=0t = 0 carefully since sin(0)0\frac{\sin(0)}{0} is undefined. However, we know from calculus that limt0sin(t)t=1\lim_{t \to 0} \frac{\sin(t)}{t} = 1, so we can evaluate it as 1 at t=0t = 0.

  2. Set n=4n = 4, so h=104=0.25h = \frac{1 - 0}{4} = 0.25.

  3. Evaluate the points: We need to compute f(t)f(t) at t=0,0.25,0.5,0.75,1t = 0, 0.25, 0.5, 0.75, 1:

    • f(0)=1f(0) = 1
    • f(0.25)=sin(0.25)0.25f(0.25) = \frac{\sin(0.25)}{0.25}
    • f(0.5)=sin(0.5)0.5f(0.5) = \frac{\sin(0.5)}{0.5}
    • f(0.75)=sin(0.75)0.75f(0.75) = \frac{\sin(0.75)}{0.75}
    • f(1)=sin(1)1f(1) = \frac{\sin(1)}{1}
  4. Apply Simpson's Rule:

I0.253[f(0)+4(f(0.25)+f(0.5)+f(0.75))+f(1)]I \approx \frac{0.25}{3} \left[ f(0) + 4(f(0.25) + f(0.5) + f(0.75)) + f(1) \right]

Now, we can compute the numerical values for each of these functions:

  • f(0.25)sin(0.25)0.251.0032f(0.25) \approx \frac{\sin(0.25)}{0.25} \approx 1.0032
  • f(0.5)sin(0.5)0.50.9589f(0.5) \approx \frac{\sin(0.5)}{0.5} \approx 0.9589
  • f(0.75)sin(0.75)0.750.9732f(0.75) \approx \frac{\sin(0.75)}{0.75} \approx 0.9732
  • f(1)sin(1)10.8415f(1) \approx \frac{\sin(1)}{1} \approx 0.8415

So,

I0.253[1+4(1.0032+0.9589+0.9732)+0.8415]I \approx \frac{0.25}{3} \left[ 1 + 4(1.0032 + 0.9589 + 0.9732) + 0.8415 \right]

Now, simplifying:

I0.253[1+4(2.9353)+0.8415]I \approx \frac{0.25}{3} \left[ 1 + 4(2.9353) + 0.8415 \right]

I0.253[1+11.7412+0.8415]I \approx \frac{0.25}{3} \left[ 1 + 11.7412 + 0.8415 \right]

I0.253[13.5827]I \approx \frac{0.25}{3} \left[ 13.5827 \right]

I3.395731.1319I \approx \frac{3.3957}{3} \approx 1.1319

So, the approximate integral value is 1.1319.

Would you like more details or help with any other question? Here are a few related questions you might find interesting:

  1. How does Simpson's Rule compare to other numerical integration methods like the trapezoidal rule?
  2. What happens when you use a higher value for nn in Simpson's Rule?
  3. How can Simpson’s Rule be modified for non-uniform intervals?
  4. How do we deal with the singularity at t=0t = 0 for functions like sin(t)t\frac{\sin(t)}{t}?
  5. What is the effect of increasing the number of intervals in improving accuracy?

Tip: When using Simpson’s Rule, the accuracy improves significantly with an increase in nn, but keep in mind that nn must always be an even number.

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Math Problem Analysis

Mathematical Concepts

Numerical Integration
Simpson's Rule
Limits

Formulas

Simpson's Rule: \int_a^b f(x) \, dx \approx \frac{h}{3} \left[ f(x_0) + 4 \sum_{i=1,3,5,...,n-1} f(x_i) + 2 \sum_{i=2,4,6,...,n-2} f(x_i) + f(x_n) \right]
Step size: h = \frac{b - a}{n}

Theorems

Simpson's Rule
Limit of \frac{\sin(t)}{t} as t approaches 0

Suitable Grade Level

Grades 11-12