Boole's Rule is a 4th-degree Newton-Cotes closed integration formula that approximates the definite integral ∫abf(x)dx by fitting a 4th-order polynomial across 5 equally spaced points over every subinterval block.
A fundamental requirement of Boole's Rule is that the number of subintervals n must be a multiple of 4 (e.g. n=4,8,12).
Formula for Boole's Rule:
I≈452h[7y0+32y1+12y2+32y3+7y4+…] Where:
- a is the lower limit of integration.
- b is the upper limit of integration.
- n is the number of subintervals (must be a multiple of 4).
- h=nb−a is the step size.
Example of Boole's Rule
Evaluate Definite Integral
∫04ex,dx With n=4 subintervals
Step 1: Find Step Size (h)
h=44−0=1.0 Step 2: Determine Grid Points (xi)
x0=0,x1=1,x2=2,x3=3,x4=4 Step 3: Evaluate Function Values (yi=exi)
y0=1.0,y1=2.71828,y2=7.38906 y3=20.08554,y4=54.59815 Step 4 & 5: Apply Boole's Formula
I≈452(1.0)[7(1)+32(2.71828)+12(7.38906)+32(20.08554)+7(54.59815)] I≈452[1207.8767]≈53.6834 Conclusion
∫04ex,dx≈53.6834 Therefore, using Boole's Rule with n=4, the approximate value of the integral is 53.6834 (exact value e4−1≈53.59815).
Interactive Boole's Rule Calculator