I just needed to compute (get an approximating value)
I've taken a class in Maxima, but erm... either we didn't do integrals, either I forgot what we did lol!
(the second option may be the more relevant ^^)
I typed this (for the second one)
and it gives something with the erf function (nothing surprising)
integrate(exp(x^2)*2/3, x, 1, 2)
and when adding the float(...), it gives the erf function as well...
And it looks like it works with Maple, but I don't have Maple, I'm a poor student... xD
Anyway, do you know some good (and free) website where it is possible to compute such things ?