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Re: NestList integration bug?

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  • Subject: [mg117548] Re: NestList integration bug?
  • From: DrMajorBob <btreat1 at>
  • 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.


On Mon, 21 Mar 2011 06:16:57 -0500, Jon Joseph <josco.jon at> 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

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