simpsons rule wrong in excel text book? (1 Viewer)

[1800-gumby]

I've been studying out of the excel step by step study guide and it has simpsons rule as h/3[(sum of ends) + 4(sum of odds) + 2(sum of evens)] my other text book i got from school (its a no name brand) gives it as h/3[(sum of ends) 2(sum of odds) + 4(sum of evens)]


Which ones right? i think the excel ones wrong but im not sure.

 

[Xayma]

If you have n function values then the even numbered ones, 2nd, 4th etc will be multiplied by 4.

 

[JayWalker]

I've been studying out of the excel step by step study guide and it has simpsons rule as h/3[(sum of ends) + 4(sum of odds) + 2(sum of evens)] my other text book i got from school (its a no name brand) gives it as h/3[(sum of ends) 2(sum of odds) + 4(sum of evens)]


Which ones right? i think the excel ones wrong but im not sure.

Yeah thats confused by most people. It depends if you do it like this..

Start with first function value as Fo then F1 F2 F3... Or
Start wiith function value as F1, then F2 F3

Depends if you start with your first function value as 1 or 0..

If you start as 0 then it is h/3[(Sum of Ends) + 4(Events) + 2(Odds)]
If you start with 1 then its h/3[(Sum of Ends) +4(Odds) + 2(Evens]

To avoid confusion, i just remember it as:

1 2 4 2 4 2 4 ... 2 4 2 1 (These are weightings)

Still confused then just start with F1 as your first and remember FOTE (Four Odds Two Evens)...

Understand?

 

[JamiL]

yep, it u start with F0 (or also refered 2 as y0) or F1, if u start with f1 then its 4(evens)+ 2(odds), if u start with F0 its 4(odds)+ 2(evens)

 

[cheeky_panda]

If you have the green textbook its wrong, ive experienced the same prob

 

[1800-gumby]

ok thanx now i see where i've been going wrong i learnt starting with f0 then forgot the formula and used the one for f1.
Thanx again

 

[smallcattle]

I dont understand what you guys are talking about...

i thought simpsons rule is (b-a)/6 * (F(a) + 4F((a+b)/2) + F(b)

whats h/3???

 

[JayWalker]

I dont understand what you guys are talking about...

i thought simpsons rule is (b-a)/6 * (F(a) + 4F((a+b)/2) + F(b)

whats h/3???

HAHAAH.. yep, your screwed...

nah jokin
I think this is where you have gone wrong: Year 7 Maths... *joke* no really here is where i think your confused:

see you are only understanding Simpsons rule for a curve with only 3 function values

h = (b-a) / number of 'strips', hence with your curve, making h = 1/2, hence h/3 = 1/6.. actually i really have no clue..

someone please help her.. i have no idea WHERE she got (b-a)/6, but i know where her 4F((a+b)/2) came from, that would ONLY work with 3 function values. i.e the middle function value is avg of ends..

Good luck :uhhuh:

 

[Xayma]

I dont understand what you guys are talking about...

i thought simpsons rule is (b-a)/6 * (F(a) + 4F((a+b)/2) + F(b)

whats h/3???

It is.

We use that same formula.

h=(b-a)/2, it just makes it more confusing.

 

[JayWalker]

Ya, what he said

 

[smallcattle]

i am still confused.... so for example x=-1, -0,5, 0, 0.5, 1 using 5 values of simpsons rule

shouldnt i do (0-(-1)/6 * (f(-1) + 4f(-0.5) + f(0)) + (1-0)/6 * (f(0) + 4f(0.5) + f(1)) ????

 

[Xayma]

it would be 1/6*(f(-1)+4f(-0.5)+f(0))+1/6*(f(0)+4f(0.5)+f(1))
=1/6(f(-1)+4(f(0.5)+f(-0.5))+2f(0)+f(1))

 

[smallcattle]

its Q7 iv in the Independent paper 2004

but the answer showed as 1/2(f(-1) + 4(f(0.5)+f(-0.5)) +2f(0) + f(1))... thats why im confused

 

[NeRdY]

It depends on how you have actually learnt it.

say you have:
F E O E L
X 1 2 3 4 5
Y -BLAH-

Where
F=first
E=even
O=odd
L=last

So then you apply this to the rule:

h/3{F + L + 4(even) + 2(odd) }

the way i always remember it you say:

"TODD" and "FLEA"

hope that helped!

 

[charmed_cuties]

my teacher taught us the simpson's rule as b - a/6{f(a)+4f(a+b/2)+f(b)} but sum how i keep getting the wrong answer

 

[DeadFish]

The universal one is:

h/3 [ f(A) + f(B) + 4*(first one after a) + 2*(the second) + 4* + 2* +...], where h is B-A/n. This should get you a corect answer every time. But even more importantly, you only have to use it once!

My opinions on the Simpson's Rule: This is very very poorly taught by the textbooks and teachers. Students get mixed up on virtually everything in this.

-with this equation, remember h as the width of one strip, NOT b-a/n
-don't bother with the odds evens crap. just remember it as a + b + then 4,2,4,2, starting from the first x-value after A to the value before b.

 

[alex tonkin]

if you're unsure just do a few practise questions and see if u get the right answer.

 

[Shimtek]

ive been shown too many ways

i was taught this way i tihnk.. so many ways to write it that its confusing

(b-a)/2*(f(a)+4f((a+b)/2) + f(b))