OK... that seems much better indeed! Unfortunately I won't throw away my version and buy maple 12 just for that! Thanks

Hi, Thanks for your help but I am still wondering if there is a way to increase the number of points maple calculates in the range between 1 and 10^5 because as you can see on the corrected file (link below), only two are evaluated and I think it really impacts the graph smoothness: (ther shouldn't be such an elbow...) View 9432_radioactivitycorrected.mw on MapleNet or Download 9432_radioactivitycorrected.mw
View file details Thanks

Well, they're not: this link shows the good plots: http://www.mapleprimes.com/files/9432_Image%201.jpg But I figured out what the problem was and it is stupid... I forgot the * sign between the (lambda2-lambda1) in the denominator of r3... I don't know what mapple thought it was... Still, I was wondering if it is possible to make these curves smoother in particular for low t values? Thanks for your help though!

I thank you for trying to help me! here are the links to my file that I just uploaded: View 9432_radioactivity.mw on MapleNet or Download 9432_radioactivity.mw
View file details hope you'll be able to help me with that! Thanks Raphael