HOME and CAS unexpected behavior

[mmadurga]

Hi all,

One of my students mentioned to me that he was getting zero when calculating the result of a finite integral in HOME.

I already had the solutionI calculated using a table of integrals so I could easily evaluate it in both HOME and CAS, and, lo and behold, I get 0.000E0 in HOME, 7.1054E-15 in CAS.

The expression to evaluate is

EXP(-2r/a) * (-2r^2/a^2 - 2r/a - 1) + 1

with r=0.877E-15 and a =5.290E-11

Any idea where is this behavior coming from?[/code]