> It looks to me like you reported a discrepancy which everyone else would
startby considering a bug
Well, at the time of writing, title and post itself seemed to me rather
neutral. My fault
> Demo is hardly the simplest
I admit, i should have reported it in more readable form.
I don't have time to find the MWE right now, but i think it would be
better, if i at least post there purified version of the code i provided
before.
The simplest form i found right now is:
f(x) = sign(x^2 - 4)
v = (x*f).integrate(x, 0, 3)
show(v)
Which yields (wrong) answer $\frac{-9}{2}$, derived by directly applying
Newton-Leibnitz
That's what Maxima returns
And then we can apply same technique as before
(multiply $x^2$ by $cos^2+sin^2$)
to make SAGE magically return correct answer:
f(x) = sign(x^2*cos(x)^2 + x^2*sin(x)^2 - 4)
v = (x*f).integrate(x, 0, 3).simplify_full()
show(v)
Evaluates to $\frac{1}{2}$ (correct).
NB: in this case ```integrate``` returns integral expression, which is then
simplified into number
понедельник, 11 апреля 2016 г., 17:16:43 UTC+3 пользователь rjf написал:
>
> [snipped]
>
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