Trapezium rule

The trapezium rule is a method of finding the approximate value of the value of an integral between certain limits. In other words the trapezium rule is a way of calculating the area under the curve on a graph. You must know that an integration gives the area under a curve on a graph. The following is the trapezium rule.
[formulae id=”11″]

The trapezium rule takes advantage of the are of a trapezium formula:

Area of trapezium = h(a + b)/2

The rule works by splitting the area under a curve into a number of trapeziums we could find the area for. For example consider the graph in the following diagram,
Graph split into trapeziums
The area below the graph curve has been split into a number of trapeziums. These trapeziums have been noted by letters A, B, C, and D

Trapezium rule Examples

Find the area between the x-axis and the curve y = x2 + 2 between x = 1 and x = 5 using the trapezium rule with 4 strips./

Example

Answer

    Explanation

    First let’s draw a table to find out the y values.

    x 1 2 3 4 5
    y 3 6 11 18 27

    So now we can use the trapezium rule. The trapezium rule states that as above:

    Area = h/2(y0 + y4 + 2(y1 + y2 + y3))

    The h is the height of the trapeziums or very simply the intervals between the x values. In the above table we have x values ranging from: 1, 2, 3, 4, and 5 The distance between these values is 1

    Area = 1/2(3 + 27 + 2(6 + 11 + 18))
    = 50 square units

    The answer for the area between the curve of y = x2 + 2 is 50 square units

    You may also like...

    4 Responses

    1. steven says:

      wow, this is great and easie

    2. admin says:

      Thanks, I am glad you found it easy. I have just added a few missing details that I forgot to add. I hope you understood everything.

    3. Myrna says:

      this ti the first time i come across Trapezium unfortunately i still do not understand the process

    4. Diksha says:

      Thank u.. Finally I got the trapezium rule.. The explanation was straight to the point..

    Leave a Reply to steven Cancel reply

    Your email address will not be published. Required fields are marked *