Composite form of Boole's Rule

In summary, a composite form of Boole's rule has been developed for an integral where the bounds of integration are from [a,b]. To determine the error bound formula, the interval should be split into 4n pieces of length h = (b-a)/(4n). The error bound formula is given by -(8h7/945)*d6g/dt6 (ξ) for some ξ ∈ [0,4h].
  • #1
says
594
12

Homework Statement


Develop a composite form of Boole's rule for an integral of the form ∫ f(x) dx, where the bounds of integration are from [a,b].

Determine the error bound formula for the composite form of Boole's rule.

∫ g(t) dt = h/45[14g(0)+64g(h)+24g(2h)+64g(3h)+14g(4h)] - (8h7/945)*d6g/dt6 (ξ)

for some ξ ∈ [0,4h]
bounds of integration are [0,4h]

Homework Equations


∫ g(t) dt [bounds of integration [a,b]
a=a
b=a+nh

The Attempt at a Solution


∫ g(t) dt = h/45[14g(0)+64g(h)+24g(2h)+64g(3h)+14g(4h)]

∫ g(t) dt = 2h/45[7g(0)+32g(h)+12g(2h)+32g(3h)+7g(4h)]

∫ g(t) dt = 2h/45[7g(a)+32g(a+h)+12g(a+2h)+32g(a+3h)+7g(a+4h)]

∫ g(t) dt = 2h/45[7g(a)+32g(a+h)+12g(a+2h)+32g(a+3h)+7g(a+4h)]

∫ g(t) dt = 2h/45[7g((a)+(a+4h))+32g((a+h)+(a+3h))+12g(a+2h)]

I think that is the composite of Boole's rule. I'm not sure how to determine the error bound formula for the composite form of Boole's rule though. Any help would be much appreciated :)
 
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  • #2
says said:

Homework Statement


Develop a composite form of Boole's rule for an integral of the form ∫ f(x) dx, where the bounds of integration are from [a,b].

Determine the error bound formula for the composite form of Boole's rule.

∫ g(t) dt = h/45[14g(0)+64g(h)+24g(2h)+64g(3h)+14g(4h)] - (8h7/945)*d6g/dt6 (ξ)

for some ξ ∈ [0,4h]
bounds of integration are [0,4h]

Homework Equations


∫ g(t) dt [bounds of integration [a,b]
a=a
b=a+nh

The Attempt at a Solution


∫ g(t) dt = h/45[14g(0)+64g(h)+24g(2h)+64g(3h)+14g(4h)]

∫ g(t) dt = 2h/45[7g(0)+32g(h)+12g(2h)+32g(3h)+7g(4h)]

∫ g(t) dt = 2h/45[7g(a)+32g(a+h)+12g(a+2h)+32g(a+3h)+7g(a+4h)]

∫ g(t) dt = 2h/45[7g(a)+32g(a+h)+12g(a+2h)+32g(a+3h)+7g(a+4h)]

∫ g(t) dt = 2h/45[7g((a)+(a+4h))+32g((a+h)+(a+3h))+12g(a+2h)]

I think that is the composite of Boole's rule. I'm not sure how to determine the error bound formula for the composite form of Boole's rule though. Any help would be much appreciated :)

I think that what the question wants you to find is a formula for ##\int_a^b f(x) \, dx## obtained by splitting the interval ##[a,b]## into ##4n## pieces of length ##h = (b-a)/(4n)## each. So, instead of having just 4 intervals you might have 40 or 400 intervals---some multiple of 4, anyway.
 
  • #3
Ray Vickson said:
I think that what the question wants you to find is a formula for ∫baf(x)dx∫abf(x)dx\int_a^b f(x) \, dx obtained by splitting the interval [a,b][a,b][a,b] into 4n4n4n pieces of length h=(b−a)/(4n)h=(b−a)/(4n)h = (b-a)/(4n) each. So, instead of having just 4 intervals you might have 40 or 400 intervals---some multiple of 4, anyway.

Ok, so I think I've got a formula that splits the interval up in 4n pieces of length h. I've inserted it below (I=...)

I = (2h/45) [7f(a)+32f(a+h)+12f(a+2h)+32f(a+3h)+7f(a+4h)] + (2h/45) [7f(a+4h)+32f(a+5h)+12f(a+6h)+32f(a+7h)+7f(a+8h)] + ... + (2h/45) [7f(a+(n-4)h)+32f(a+(n-3)h)+12f(a+(n-2)h)+32f(a+(n-1)h)+7f(a+nh)]

I = (2h/45)[7f(a+(n-4)h)+32f(a+(n-3)h)+12f(a+(n-2)h)+32f(a+(n-1)h)+7f(a+nh)]

I'm not sure how I would determine the error bound formula for the composite rule though.

h = (b-a)/(4n)

Error bound formula = - (8h7/945)*d6g/dt6 (ξ)
for some ξ ∈ [0,4h]
 

1. What is the Composite form of Boole's Rule?

The Composite form of Boole's Rule is a numerical integration method used to approximate the area under a curve by dividing the interval into subintervals and applying Boole's Rule to each subinterval.

2. How does the Composite form of Boole's Rule differ from the basic form?

The Composite form of Boole's Rule differs from the basic form by dividing the interval into smaller subintervals and applying Boole's Rule to each subinterval, rather than using a single interval for the entire function.

3. What are the advantages of using the Composite form of Boole's Rule?

The Composite form of Boole's Rule can provide a more accurate approximation of the area under a curve compared to the basic form, especially for functions with sharp turns or irregular shapes. It also allows for more flexibility in choosing the number of subintervals to use for a more precise result.

4. What are the limitations of the Composite form of Boole's Rule?

The Composite form of Boole's Rule may not provide an accurate approximation for functions with extremely large or small values, as the subintervals may not be able to capture the behavior of the function. It also requires more computational resources compared to the basic form, as it involves multiple calculations for each subinterval.

5. When is it most appropriate to use the Composite form of Boole's Rule?

The Composite form of Boole's Rule is most appropriate for functions with complex shapes or multiple sharp turns, as it can provide a more accurate approximation of the area under the curve. It is also useful when a more precise result is needed, as the number of subintervals can be adjusted to improve the accuracy of the calculation.

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