Simpson's Rule Calculator

Now evaluate the approximate value of the given definite integral function with the help of simpson’s rule calculator with steps.

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Table of Contents:

Introduction to Simpson's Rule Calculator:

Simpson's rule calculator is an online tool that helps you to evaluate definite integral function's approx value. It is used to find the area under a curve from the given complex quadratic polynomial function in an interval.

Simpson's Rule Calculator with Steps

When you solve the Simpson rule question manually it takes time or you may get stuck during calculations. That’s why we introduce simpson rule calculator that keeps you away from all these difficulties and provides you the solution with just one click.

What is Simpson's Rule?

Simpson rule is a numerical integration process of calculating the approximate value of area under a graph over a bonded region. Simpson rule is the extension of the trapezoidal rule as it finds the complex integral problem of the second order (quadratic polynomial) functions.

Simpson rule has two formulas that are used to estimate the approximate value for different types of quadratic polynomial functions under a parabola.

What is Simpson's 1/3 Rule?

For a function f(x) that divides intervals [a, b] into even number of subintervals, the Simpson's rule calculator uses Simpson's 1/3 rule formula as:

$$ \int_a^b f(x) dx \approx \frac{\Delta x}{3} (f(x_0) + 4f(x_1) + 2f(x_2) + 4f(x_3) + … + 2f(x_{n-2}) + 4f(x_{n-1}) + f(x_n)) $$

  • h = b-a/n: the width of the subinterval/
  • f(x): the function
  • x0, x1, x2, x3…: the value of subinterval of a given function
  • [a,b]: the interval of a given function

What is Simpson's 3/8 Rule?

Simpson's 3/8 Rule is a method for approximating the cubic polynomials and definite integral of a function. It is particularly useful when the subintervals are a multiple of 3.

Simpson's 3/8 rule gives more accurate result than simpson's 1/3 rule but it is used for odd number values only. The simpsons rule calculator uses 3/8 rule also if the question is supposed to solve by the given formula,

$$ \int_a^{b} f(x) dx \;=\; \frac{3 \Delta x}{8} [f(x_0) + 2(f(x_3) + f(x_6) + f(x_{n-1})) + f(x_n)] $$

How to Calculate Simpson's Rule?

Simpson's rule formulas is used to solve complex integral functions, quadratic polynomial functions or cubic polynomial functions. simpson 1/3 rule and simpson 3/8 rule have two separate formulas for complex calculations.

Let's see examples of the simpson rule where we would use both the rules solve a problem to understand how the simpson's 1/3 rule calculator solves such questions.

Example of Simpson’s Rule:

An example of simpson’s rule is given below so that you may know how the simpson’s rule calculator works.

Example: Find the following integral using simpson’s rule with n = 4.

$$ \int_0^4 (1 + x^2) dx $$

Solution:

Step 1:

Determine the values from the given integral function. In this example, the values are:

$$ n \;=\; 4,\; a \;=\; 0\; and\; b \;=\; 4,\; f(x) \;=\; 1 + x^2 $$

Step 2:

Find the width of subinterval h as h = b-a/n,

$$ h \;=\; \frac{4-0}{4} \;=\; 1 $$

$$ h \;=\; 1 $$

Step 3:

Then, find the subinterval of a given function f(x) such as:

$$ f(x) \;=\; f(x_0), f(x_1), f(x_2), f(x_3), f(x_4) $$

$$ x_0, x_1 \;=\; 1, x_2 \;=\; 2, x_3 \;=\; 3, x_4 \;=\; 4 $$

$$ f(0) \;=\; 1 + 0^2 \;=\; 1 $$

$$ f(1) \;=\; 1 + 1^2 \;=\; 2 $$

$$ f(2) \;=\; 1 + 2^2 \;=\; 5 $$

$$ f(3) \;=\; 1 + 3^2 \;=\; 10 $$

$$ f(4) \;=\; 1 + 4^2 \;=\; 17 $$

Step 4:

Apply the 1/3 Simpson rule and modify it as per the given function and its subintervals such as,

$$ \int_a^b f(x) dx \;=\; \frac{h}{3} [(y_0 + y_n) + 4(y_1 + y_3 + y_5 + … + y_{n-1}) + 2(y_2 + y_4 + y_6 + … + y_{n-2})] $$

Step 5:

Add all the values in the 1/3 Simpson rule formula to get the solution,

$$ \int_0^4 (1 + x^2) dx \approx \frac{1}{3} [1 + 4(2 + 10) + 2(5) + 17] $$

Step 6:

Therefore, the solution of definite integral over a subinterval n = 4 is:

$$ \int_0^4 (1 + x^2) dx \approx \frac{1}{3} [1 + 48 + 10 + 17] $$

$$ \int_0^4 (1 + x^2) dx \approx \frac{1}{3} \times 76 \;=\; \frac{76}{3} \approx 25.333 $$

Example: Find the following integral using Simpson’s ⅜ rule with n = 3.

$$ \int_0^3 e^x dx $$

Solution:

Step 1:

Determine the values from the given integral function. In this example, the values are,

$$ n \;=\; 3,\; a \;=\; 0\; and\; b \;=\; 3,\; f(x) \;=\; e^x $$

Step 2:

Find the width of subinterval h as:

$$ h \;=\; \frac{b-a}{n} $$

$$ h \;=\; \frac{3-0}{3} \;=\; 1 $$

$$ h \;=\; 1 $$

Step 3:

Then, find the subinterval of a given function f(x) such as:

$$ f(x) \;=\; f(x_0),\; f(x_1),\; f(x_2),\; f(x_3) $$

$$ x_0 \;=\; 0,\; x_1 \;=\; 1,\; x_2 \;=\; 2,\; x_3 \;=\; 3 $$

$$ f(0) \;=\; e^0 \;=\; 1 $$

$$ f(1) \;=\; e^1 \;=\; e $$

$$ f(2) \;=\; e^2 \;=\; e^2 $$

$$ f(3) \;=\; e^3 \;=\; e^3 $$

Step 4:

Apply the ⅜ Simpson rule and modify it and its subintervals as per the given function:

$$ \int_0^3 e^x dx \approx \frac{3h}{8} [f(0) + 3(f(1) + f(2)) + f(3)] $$

Step 5:

Add all the values in the 3/8 Simpson rule formula.

$$ \int_0^3 e^x dx \approx \frac{3.1}{8} [1 + 3(e + e^2) + e^3 ] $$

Step 6:

Therefore, the solution of definite integral over a subinterval n = 3 is,

$$ \int_0^3 e^x\; dx \approx \frac{3}{8} [1 + 3e + 3e^2 + e^3] $$

How to Use Simpson's Rule Calculator?

The simpson rule calculator has a simple design that makes it easy for you to use it for evaluating the complex integral functions. You need to follow our guidelines before using it. These guidelines are:

  • Enter the complex integral function of the subinterval in the given input field.
  • Enter the value of the upper and lower limit of integral of simpson rule in the input field.
  • Enter the subinterval value in the required field.
  • Recheck the given integral expression before clicking the calculate button of simpsons rule calculator.
  • Click the “Calculate” button to get the result of your given complex integral over a single interval.
  • If you are trying our simpson's 1/3 rule calculator for the first time then you can use the load example option to learn more about this concept.
  • Click on the “Recalculate” button to get a new page for finding solutions of complex integral problems using the Simpson rule.

Final Result of Simpson Rule Calculator:

When you add the input, the simpson calculator gives you the solution from the given integral function. The results are shown as:

  • Result Option:

When you click on the result option the simpson 1/3 rule calculator gives you the solution of the integral function.

  • Possible Steps:

When you click on it, this option will give you step by step solution of simpson's rule problem.

Advantages of Simpsons Rule Calculator:

The simpson's rule error calculator provides you with many advantages and helps you to calculate integral problems. These advantages are:

  • The simpson's method calculator is a free tool so you can use it to find the solution of integral for free.
  • It is a manageable tool that can manage various types of integral problems that have quadratic polynomial or cubic functions. It conatins a built-in Simpson rule to solve these problems easily.
  • Our simpson calculator gives you conceptual clarity for the integral process by giving you an oppportunity to solve multiple examples.
  • It saves the time that you consume in the calculation of complex integral problems and provides solutions in a few seconds.
  • Simpson 1/3 rule calculator is a reliable tool that provides you accurate solutions of integral problems without any errors.
  • You can use the simpson's rule calculator multiple times for evaluating antiderivative problems over a bounded region.
Related References
Frequently Ask Questions

What is the error with simpsons 1/3 rule

Simpson's 1/3 Rule, also known as Simpson's Rule, is a numerical integration technique that approximates the integral of a function f(x) on an interval [a,b] of quadratic interpolating polynomials. The rule is formulated as:

$$∫_b^a f(x) dx \approx \frac{b - a}{6} \left[f(a) + 4f (\frac{a+b}{2}) + f(b) \right] $$

  • It only applies for an even number of subintervals to work correctly. If the number of intervals n is odd, then the rule would need to be adapted using the Trapezoidal Rule.
  • If the function f(x) being integrated is a discontinuity function, sharp changes, or high-frequency oscillations, then Simpson's 1/3 Rule may not provide accurate results.
  • Problems may arise if f(x) is not continuous at the endpoints a and b.
  • Simpson's 1/3 Rule is designed for points xi=a+i⋅b. The rule may not apply directly without modification.

In short, Simpson's 1/3 Rule is a widely used method for numerical integration, it is important to consider its limitations when applying it to different types of functions and integration problems.

When to use simpson's 3/8 rule

Simpson's 3/8 Rule is a numerical integration method that is used to integrate a function f(x) over an interval [a,b] using cubic interpolating polynomials. It is used for:

  • Similar to Simpson's 1/3 Rule, Simpson's 3/8 Rule requires an even number of subintervals, If the number of intervals n is not a multiple of 3, that is an additional technique
  • Simpson's 3/8 Rule performs well for smooth and continuous functions f(x). It can accurately approximate the integral even when f(x) has smooth curves within the interval.
  • It provides more precise results due to the inclusion of additional function evaluations as compared to ⅓ Simpson rule.
  • It helps students understand the principles of numerical integration using higher-order polynomial approximations.

Does simpson's rule trapezoid rule and midpoint rule have the same?

No, Simpson's rule, the trapezoidal rule, and the midpoint rule are all numerical methods used for approximating definite integrals of functions. Here's a comparison of these methods:

  • Midpoint Rule:

The midpoint rule approximates the integral by evaluating the function at the midpoint of each subinterval and multiplying by the width of the interval.

If the interval [a,b] is divided into n equal subintervals of width h=b−a/n the midpoint rule is given by:

$$ \int_b^a f(x) dx \approx h \sum_{i=1}^n f \left(a + (i - \frac{1}{2}) h \right) $$

  • Trapezoidal Rule:

The trapezoidal rule approximates the integral by approximating the area under the curve with trapezoids formed when you connect the points of the function at the endpoints of each subinterval.

$$ \int_b^a f(x) dx \approx \frac{h}{2} f(a) + 2 \sum_{i=1}^{n-1} f(a + ih) + f(b) $$

  • Simpson's Rule (1/3 Rule):

Simpson's rule approximates the integral using quadratic interpolating polynomials over each pair of subintervals [a,b].

$$ \int_b^a f(x) dx \approx \frac{h}{3} \left[ f(a) + 4 \sum_{i=1}^{\frac{n}{2-1}} f(a + 2ih) + 2 \sum_{i=1}^{\frac{n}{2}} f(a + (2i - 1)h) + f(b) \right] $$

In summary, the choice of which rule to use depends on the desired level of accuracy, and the nature of the function being integrated. Simpson's rule is preferred when higher accuracy is required and when n s even

Why is simpson's rule more accurate than trapezoidal

Simpson's Rule is more accurate than the Trapezoidal Rule because it approximates the integrand f(x) using quadratic polynomials over each subinterval, whereas the Trapezoidal rule uses linear interpolating polynomials.

  • Simpson's Rule approximates f(x) using quadratic polynomials P(x)) over each pair of subintervals. Quadratic polynomials can better match the curvature of the function f(x) that is used in the Trapezoidal Rule.
  • Simpson's Rule has a higher convergence rate compared to the Trapezoidal Rule.
  • This means that as the width h of the subintervals decreases, Simpson's Rule achieves a higher rate of decrease in the error compared to the Trapezoidal Rule.
  • Quadratic interpolation in Simpson's Rule reduces oscillatory errors that can occur with linear interpolation in the Trapezoidal Rule.
  • Simpson's Rule is used for integrating smooth functions f(x).

This additional computational effort is often justified when higher accuracy is needed, such as in scientific computations, numerical analysis, and engineering applications where precise integration results are crucial.

What is the parabola in simpson's rule

Simpson's rule specifically Simpson's 1/3 Rule, the "parabola" refers to the quadratic polynomial P(x) hat is used to approximate the integrand f(x) over each pair of subintervals [xi,xi+2]

The formula for Simpson's 1/3 Rule is:

$$ \int_b^a f(x) dx \approx \frac{h}{3} \left[ f(a) + 4f \left(\frac{a+b}{2} \right) + f(b) \right] $$

Form of the Parabola:

The quadratic polynomial P(x) is pass through the points,

$$ (x_i, f(x_i)), \left( \frac{x_i + x_{i+1}}{2},\; f(x_i + x_{i+1}) \right), (x_{i+1},\; f(x_{i+1})) $$

This means that P(x) is uniquely determined by these three points, fitting a parabola that best approximates f(x) over the interval [xi, x_i+2].

By using quadratic interpolation Simpson's 1/3 Rule achieves a higher accuracy compared to simpler methods like the Trapezoidal Rule, which uses the linear interpolation. The overall integration formula for Simpson's 1/3 Rule sum up the each pair of subintervals, where each subinterval is approximated by the area under the corresponding quadratic P(x)

Therefore, the "parabola" in Simpson's Rule refers to the quadratic polynomial P(x) that is used to approximate the integrand f(x)) over each pair of subintervals.

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