Message-ID: <CAAmySGNSHN7JLNrYDncpHX2_2XX7SjQ3FEBx-Fe=x86QNyOhTg@mail.gmail.com>
Date: 2011-10-18T14:25:57Z
From: R. Michael Weylandt
Subject: About an integral univariate problem
In-Reply-To: <CAEb2E7avPotyaPgTLE=SRt_KQz8j_p-SKiY2A-+2TG5gbbD28g@mail.gmail.com>
How about adding an additional argument to fun?
R> fun <- function(x, y) exp(-x)*sum(y^x)
R> y <- c(2,3,5)
R> integrate(fun, 0, 3, y)
[1] 346.853 with absolute error < 3.9e-12
Michael
On Tue, Oct 18, 2011 at 10:01 AM, Freddy Hernandez Barajas
<fhernanb at gmail.com> wrote:
> Hello all R users
>
> I want to calculate this univariate integral:
> exp(-x)*sum(y^x) ?respect to x ?from 0 to 3 ?where y is a vector y=(2,3,5).
> In fact, the original y vector has a large number of elements but I propose
> with 3 elements.
>
> I know that I can resolve this problem doing
>
> fun <- function(x) exp(-x)*(2^x+3^x+5^x)
> integrate(fun,0,3)
>
> When the y vector has a large number of elements the last solution is not
> possible,
> if I use this another way I can not obtain the true answer
>
> ? y <- c(2,3,5)
> fun1 <- function(x) exp(-x)*sum(y^x)
> integrate(fun1,0,3)
>
> Someone could give me a help with the problem?
> Thanks.
>
>
> Freddy Hern?ndez Barajas
>
> ? ? ? ?[[alternative HTML version deleted]]
>
>
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