Hello, how to write a code to find an excat value of this integral?
I really need help with this one! I wrote a code to approximate the value but i can't create a code to find the exact one

8 commentaires

Walter Roberson
Walter Roberson le 20 Mar 2019
How do you want the exact value expressed? erf? hypergeometric function? Fresnel C function?
Erika Plekaviciute
Erika Plekaviciute le 20 Mar 2019
Modifié(e) : Erika Plekaviciute le 20 Mar 2019
The exact value must be a number equal to this: ?????? ~ 0.904524237900272
I created a code but it calculates only the approximate value, so I keep getting: 0.904524456832745
Walter Roberson
Walter Roberson le 20 Mar 2019
That isn't the exact value. The exact value is likely an irrational number when expressed in decimal; sqrt(pi) is part of the expression of it. Any finite truncation of it would be only an approximation.
What is your numeric approximation code? You only need 9 terms to get that particular numeric value.
Torsten
Torsten le 21 Mar 2019
Because you write down a series representation of the integral, maybe your task is to add up until you get the required accuracy ?
Walter Roberson
Walter Roberson le 21 Mar 2019
You are just doing a summation of values at end points as if the value were constant for the entire interval. That is not going to be accurate. You should look at the trapizoid rule for greater accuracy. trapz()
Torsten
Torsten le 21 Mar 2019
You are trying to approximate the integral, not summing up the series.
James Tursa
James Tursa le 21 Mar 2019
Erika, it is very poor online etiquette to delete your question after there have been comments and answers posted. This is a disservice to the Answers community.
Rena Berman
Rena Berman le 2 Avr 2019
(Answers Dev) Restored edit

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 Réponse acceptée

Torsten
Torsten le 21 Mar 2019
Modifié(e) : Torsten le 22 Mar 2019

0 votes

format long
I = 0.0;
Iexact = 0.904524237900272;
eps = 1e-15;
n = 0;
while abs(I-Iexact) > eps
I = I + (-1)^n/(factorial(2*n)*(4*n+1))
n = n+1;
end
n-1
I

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