Simpson's 3/8 Rule Calculator for a Table

Approximate an integral (given by a table of values) using the Simpson's 3/8 rule step by step

For the given table of values, the calculator will find the approximate value of the integral using Simpson's 3/8 rule, with steps shown.

Related calculators: Simpson's Rule Calculator for a Table, Simpson's 3/8 Rule Calculator for a Function

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

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Your Input

Approximate the integral 012f(x)dx\int\limits_{0}^{12} f{\left(x \right)}\, dx with the Simpson's 3/8 rule using the table below:

xx002244668810101212
f(x)f{\left(x \right)}552-21166773344

Solution

The Simpson's 3/8 rule approximates the integral using cubic polynomials: abf(x)dxi=1n133Δxi8(f(x3i2)+3f(x3i1)+3f(x3i)+f(x3i+1))\int\limits_{a}^{b} f{\left(x \right)}\, dx\approx \sum_{i=1}^{\frac{n - 1}{3}} \frac{3 \Delta x_{i}}{8} \left(f{\left(x_{3i-2} \right)} + 3 f{\left(x_{3i-1} \right)} + 3 f{\left(x_{3i} \right)} + f{\left(x_{3i+1} \right)}\right), where nn is the number of points and Δxi\Delta x_{i} is the length of subinterval no. 3i23 i - 2.

012f(x)dx3(20)8(f(0)+3f(2)+3f(4)+f(6))+3(86)8(f(6)+3f(8)+3f(10)+f(12))\int\limits_{0}^{12} f{\left(x \right)}\, dx\approx \frac{3 \left(2 - 0\right)}{8} \left(f{\left(0 \right)} + 3 f{\left(2 \right)} + 3 f{\left(4 \right)} + f{\left(6 \right)}\right) + \frac{3 \left(8 - 6\right)}{8} \left(f{\left(6 \right)} + 3 f{\left(8 \right)} + 3 f{\left(10 \right)} + f{\left(12 \right)}\right)

Therefore, 012f(x)dx3(20)8(5+(3)(2)+(3)(1)+6)+3(86)8(6+(3)(7)+(3)(3)+4)=36.\int\limits_{0}^{12} f{\left(x \right)}\, dx\approx \frac{3 \left(2 - 0\right)}{8} \left(5 + \left(3\right)\cdot \left(-2\right) + \left(3\right)\cdot \left(1\right) + 6\right) + \frac{3 \left(8 - 6\right)}{8} \left(6 + \left(3\right)\cdot \left(7\right) + \left(3\right)\cdot \left(3\right) + 4\right) = 36.

Answer

012f(x)dx36\int\limits_{0}^{12} f{\left(x \right)}\, dx\approx 36A