MaplePrimes - answers and comments on Question, Do you know any antiderivative that maple can't find but we can?

PS. I think I need an indefinite integral

help me — Sun, 02 Mar 2008 12:17:33 Z

Thanks for your help!

My homework

Robert Israel — Sun, 02 Mar 2008 12:19:54 Z

This is homework that I assigned. Please don't do it for this student.

That indefinite integral

lemelinm — Tue, 04 Mar 2008 20:47:59 Z

HI Robert,

When the delay will be over, I would be very interested by one exemple. Could you send it directly to me?.

Mario Lemelin

mario.lemelin@cgocable.ca

Another example

hirnyk — Sat, 17 Apr 2010 07:25:15 Z

Any antiderivative is continuous, but the result of

>int(abs(sin(x)),x);

isn't continuous.

Examples

Robert Israel — Wed, 05 Mar 2008 23:39:06 Z

It's really not hard to get examples. The basic strategy is: take a random function F of one variable, involving some square roots and some transcendental functions, then try

f := simplify(diff(F,x));

There's a pretty good chance that int(f, x) will come back unevaluated.

For example:

int(1/(ln(x)+2*x)^(3/2)*(1+2*x)/x,x) = -2/(ln(x)+2*x)^(1/2)

Please note: I do not regard this as evidence of a bug in Maple.
It merely shows that the Risch algorithm is not completely
implemented.

sorry

acer — Sun, 02 Mar 2008 12:52:32 Z

Sorry, Robert.

acer