Re: NestList integration bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg117548] Re: NestList integration bug?
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Tue, 22 Mar 2011 05:08:42 -0500 (EST)
Both answers are correct. In the first NestList, the first integral is, of
course, m (x - a).
The second is the integral of that with respect to t from a to x. m (x -
a) doesn't depend on t, so it is a CONSTANT, just as m was a constant, so
the integral is the constant times (x - a), and that's m (x - a)^2.
And so on.
In the second NestList, x is the variable of integration each time, so you
get what you're getting.
There's no contradiction.
Bobby
On Mon, 21 Mar 2011 06:16:57 -0500, Jon Joseph <josco.jon at gmail.com> wrote:
> All: Please comment on the following code:
>
> The following input: NestList[Integrate[#, {t, a, x }] &, m, 5]
> (* m is a constant *)
>
> results in {m, m(-a + x), m (-a + x)^2, m (-a + x)^3, m (-a + x)^4, m
> (-a + x)^5}
>
> which is missing the divisors as a result of the integration. However,
> doing the integral indefinitely:
>
> NestList[Integrate[#, x] &, m, 5] results in
>
>
> {m, m x, (m x^2)/2, (m x^3)/6, (m x^4)/24, (m x^5)/120}
>
> which is correct.
>
> What am I missing?
>
> "7.0 for Mac OS X x86 (64-bit) (February 19, 2009)"
>
> Jon
>
--
DrMajorBob at yahoo.com