Problem with evaluation of integration



On 17/02/2011 7:57 AM, Chi Ben wrote:
> When I'm using the integrate function to evaluate an expression, 
> sometimes Maxima gives me a value after calculation. But sometimes it 
> just gives me a formal mathematical expression. For example, when I 
> enter this:
> integrate(e^(-x),x,1,5);

Strange, because maxima knows the indefinite integral

(%i7) integrate(e^(-x),x);
(%o7) -1/(e^x*log(e))

However, if your e - which is %e in maxima - is the base of the natural 
logarithm ~ 2.718... then all is not lost

(%i8) integrate(%e^(-x),x,1,5);
(%o8) %e^-1-%e^-5