Trapezoidal Rule Calculator

With our Trapezoidal Rule Calculator, you can quickly estimate areas under curves within bounded regions and evaluate definite integrals divided into trapezoidal intervals with accuracy.

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Table of Contents:

Introduction to Trapezoidal Rule Calculator:

Trapezoidal rule calculator is an efficient tool that helps you to find the approximate value of the area under the curve in a bounded region. Our tool is used to evaluate the definite integral function that divides into trapezoidal subintervals.

Trapezoidal Rule Calculator with Steps

Trapezoid rule calculator is a beneficial tool for students, teachers, and professionals for making assignments, notes, or research reports as it gives you solutions for a given function in a few seconds without making any mistakes in evaluation.

What is the Trapezoidal Rule?

Trapezoidal rule is a numerical integration process that is used to find the estimated value of the definite integral function in a bounded region. This method is specifically used to find the area under a graph by dividing it into subintervals.

Trapezoidal rule is the extension of the Reimann sum because it provides a more accurate solution of your given function without error than using the Reimann sum rule.

Formula of Trapezoidal Rule:

The formula of a trapezoidal rule is a continuous function f(x) over an interval [a,b] that divides the area into n smaller sections such as:

$$ \int_a^b f(x) dx \approx \frac{\Delta x}{2} [f(x_0) + 2f(x_1) + 2f(x_2) + 2f(x_3) + f(x_4)] $$

  • Δx is the change between the limit as Δx=b-a
  • f(x) is the definite function
  • a and b are the upper and the lower limits

How to Calculate the Trapezoidal Rule?

Trapezoidal rule is used to calculate the definite integral function in a closed region with the help of the trapezoidal rule formula to avoid complex calculation because the regular integral is divided by a rectangle instead of a subinterval. Steps to Apply the Trapezoidal Rule:

Step 1: Determine the given function f(x), subinterval value, and the upper and the lower limit.

Step 2: Evaluate the interval with the help of the upper and the lower limit and n subinterval as Δx=b-a/n

Step 3: After finding all the values add these values into the trapezoidal rule formula.

Step 4: Solve the function after adding values into a simplified form so that you get the solution of the trapezoidal rule function.

With our trapezoidal rule calculator, automate the calculation process of definite integrals in closed regions using a straightforward formula, simplifying complex calculations by approximating the integral with trapezoids instead of subintervals.

Solved Example of Trapezoidal Rule:

The solved example of the trapezoidal rule will give you a better understanding of the trapezoidal rule and its evaluation procedure.

Example: Find the first four subintervals:

$$ \int_0^1 \sqrt{1 + x^2} dx $$

Solution:

Determine the given data from the given function

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

Find the change in function Δx = b-a/n,

$$ \Delta x \;=\; \frac{b - a}{n}, \Delta x \;=\; \frac{1 - 0}{4} $$

$$ \Delta x \;=\; 0.25 $$

Find the given integral function subinterval n as,

$$ f(x) \;=\; f(x0),\; f(x_1),\; f(x_2),\; f(x_3),\; f(x_4) $$

$$ f(x) \;=\; f(x0),\; f(x_1),\; f(x_2),\; f(x_3),\; f(x_4) $$

$$ x_0 \;=\; 0, x_1 \;=\; 0.25, x_2 \;=\; 0.5, x_3 \;=\; 0.75, x_4 \;=\; 1 $$

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

$$ f(0.25) \;=\; \sqrt{1 + (0.25)^2} \approx 1.06066 $$

$$ f(0.5) \;=\; \sqrt{1 + (0.5)^2} \approx 1.11803 $$

$$ f(0.75) \;=\; \sqrt{1 + (0.75)^2} \approx 1.25708 $$

$$ f(1) \;=\; \sqrt{1 + 1^2} \;=\; \sqrt{2} \approx 1.41421 $$

Apply all the function values, change the limit in the trapezoidal rule formula,

$$ \int_0^1 \sqrt{1 + x^2} dx \approx \frac{0.25}{2} [1 + 2(1.06066 + 1.11803 + 1.25708 + 1.41421] $$

$$ \int_0^1 \sqrt{1 + x^2} dx \approx \frac{0.25}{2} [1 + 2(3.43577) + 1.41421] $$

$$ \int_0^1 \sqrt{1 + x^2} dx \approx \frac{0.25}{2} [1+ 6.87154 + 1.41421] $$

$$ \int_0^1 \sqrt{1 + x^2} dx \approx \frac{0.25}{2} \times 9.28575 $$

$$ \int_0^1 \sqrt{1 + x^2} dx \approx 1.16071875 $$

Therefore, the approximate value of the integral ∫01√1+x2dx using the Trapezoidal Rule with n=4 subintervals is 1.16071875.

For more convenience and accuracy in calculations, try our trapezoidal method calculator.

How to Use the Trapezium Rule Calculator?

Trapezoidal calculator has an easy-to-use interface, so you can easily use it to evaluate the given definite integral problem solution. Before adding the input for the solutions of given trapezoidal rule problems, you must follow some simple steps. These steps are:

  1. Enter the definite function in the input field that you want to evaluate using the trapezoidal rule.
  2. Add the value of subinterval n for the trapezoidal rule problem in the input field.
  3. Add the value of upper and the lower limit for trapezoidal integral function.
  4. Recheck your input value for the trapezoidal rule problem solution before hitting the calculate button to start the calculation process in the trapezoidal approximation calculator.
  5. Click on the “Calculate” button to get the desired result of your given Trapezoidal rule problem.
  6. If you want to try out our trapezoidal sum calculator to check its accuracy in solution, use the load example.
  7. Click on the “Recalculate” button to get a new page for solving more trapezoidal rule questions.

Final Result of Trapezoidal Method Calculator:

Trapezoid approximation calculator gives you the solution to a given definite integral problem when you add the input value to it. It provides you with solutions that may contain as:

  • Result Option

You can click on the result option as it provides you with a solution to trapezoidal rule questions.

  • Possible Step

When you click on the possible steps option it provides you with the solution of the trapezoidal rule problem where steps are included.

Benefits of Using Trapezoidal Rule Calculator:

Trapezoid rule calculator gives you multiple benefits whenever you use it to calculate trapezoidal rule problems to get its solution. These benefits are:

  • Our trapezium rule calculator saves the time and effort that you consume in solving trapezoidal rule questions and getting solutions in a few seconds.
  • It is a free-of-cost tool that provides you a solution for a given integral to find the area of a graph using the trapezoidal rule without paying a single penny.
  • The trapezoidal calculator ensures highly accurate results when computing integrals, minimizing potential errors that can occur with manual methods.
  • It is an adaptive tool that allows you to find the definite integral function in the calculator.
  • You can use this trapezoidal approximation calculator for practice to get familiar with this concept easily when you use it multiple times.
  • Trapezoidal sum calculator is a trustworthy tool that provides you with correct solutions as per your input to calculate the Trapezoidal integral problem.
Related References
Frequently Ask Questions

What is the difference between trapezoidal rule and simpson's rule

The trapezoidal rule and Simpson's rule are both numerical methods used to approximate the definite integral of a function over a given interval.

Trapezoidal Rule

The trapezoidal rule find the estimate value of the area under the curve by dividing the interval into n equal subintervals over an interval.

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

Simpson's Rule

Simpson's rule find the approximate value from the area under the curve by using parabolic segments pairs of consecutive points.

$$ \int_a^b f(x) dx \approx \frac{b-a}{3n} \left( f(a) + 4 \sum_{i=1,odd}^{n-1} f(x_i) + 2 \sum_{i=2,even}^{n-2} f(x_i) + f(b) \right) $$

Simpson's rule is generally more accurate than the trapezoidal rule for the same number of intervals n, especially when n is small.

Why simpson's rule is better than trapezoidal

Simpson's rule is considered better than the trapezoidal rule for numerical integration due to several reasons its higher accuracy because it uses the quadratic interpolation, which leads to a smaller error for the same number of subintervals. This higher accuracy makes Simpson's rule preferred when numerical integration requires precision in solution, especially for smooth functions where higher-order approximations are beneficial.

Are trapezoidal rule and simpsoms rule the same

No,They are not the same even though both the trapezoidal rule and Simpson's rule are used for numerical integration. Simpson's rule givesmore accurate than the trapezoidal rule because it uses quadratic interpolation rather than linear. However, it requires an even number of subintervals, whereas the trapezoidal rule can be used with any number of subintervals.

Does trapezoidal rule overestimate or underestimate

The trapezoidal rule can either overestimate or underestimate value of the given definite integral depending on the concavity of the function over the interval of integration

  • Underestimates for concave up functions (f′′(x)>0).
  • Overestimates for concave down functions (f′′(x)< 0).

By understanding the behavior of the function the second derivative can help you to predict whether the trapezoidal rule will overestimate or underestimate the integral.

Can trapezoidal rule be negative

Yes, the result of the trapezoidal rule can be negative,becasue of some certain conditions. If the function f(x) takes negative values over the entire interval [a,b, the area calculated using the trapezoidal rule will be negative. For example, if f(x)=−∣x∣ over [a,b], then the integral and its approximation using the trapezoidal rule will be negative.

If the integration is performed from a higher value to a lower value (i.e, b < a, the result will be negative. For example, integrating f(x) from b to a (with b < a) will result in a negative value

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