Trapezoidal Rule Calculator for a Table

Approximate an integral (given by a table of values) using the trapezoidal rule step by step

For the given table of values, the calculator will approximate the integral by means of the trapezoidal rule, with steps shown.

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A
xx
f(x)f{\left(x \right)}

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Your Input

Approximate the integral 111f(x)dx\int\limits_{1}^{11} f{\left(x \right)}\, dx with the trapezoidal rule using the table below:

xx11335577991111
f(x)f{\left(x \right)}44002-23-3665-5

Solution

The trapezoidal rule approximates the integral using trapezoids: abf(x)dxi=1n1(xi+1xi)f(xi+1)+f(xi)2\int\limits_{a}^{b} f{\left(x \right)}\, dx\approx \sum_{i=1}^{n - 1} \left(x_{i+1} - x_{i}\right) \frac{f{\left(x_{i+1} \right)} + f{\left(x_{i} \right)}}{2}, where nn is the number of points.

Therefore, 111f(x)dx(31)0+42+(53)2+02+(75)322+(97)632+(119)5+62=1.\int\limits_{1}^{11} f{\left(x \right)}\, dx\approx \left(3 - 1\right) \frac{0 + 4}{2} + \left(5 - 3\right) \frac{-2 + 0}{2} + \left(7 - 5\right) \frac{-3 - 2}{2} + \left(9 - 7\right) \frac{6 - 3}{2} + \left(11 - 9\right) \frac{-5 + 6}{2} = 1.

Answer

111f(x)dx1\int\limits_{1}^{11} f{\left(x \right)}\, dx\approx 1A