On 01/10/2012 06:33 PM, achrzesz wrote:
On Jan 9, 6:39 pm, Renan Birck Pinheiro<[email protected]>
wrote:
Hi,
I'm trying to solve a differential equation with unit step, e.g. the
equation y'(x) = U(x-5) - where U is the unit step, and the inicial
condition y(0) is 0.
The result is 0 for 0<x<5 and x-5 for x>5 (it's a simple integral of the
unit step function). WolframAlpha gives the correct result [1], however
sage fails:
Sage can give the same results:
sage: maxima('load("abs_integrate.mac")')
sage: maxima('integrate(unit_step(t-5),t,0,x)').sage()
1/2*x + 1/2*abs(x - 5) - 5/2
I have a patch up for this if you're feeling adventurous,
http://trac.sagemath.org/sage_trac/ticket/11483
which depends on,
http://trac.sagemath.org/sage_trac/ticket/12094
The good news is I think #12094 might get some attention at sage days,
and then #11483 is less scary to get reviewed.
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