@Markiyan Hirnyk Sorry I didnt' make this clear in the question. The reason is that in my case i have lots of such integration to evaluate and these integrations are generated by my other procedures, not by typing one by one. So here, for example, the jointPDF is generated by multiplying severral PDF together, and the number of PDFs depends on the size of elist (which contains e1, e2, ...). As the size of elist changes, the integration area also changes, and they are generated correspondingly. That's why I would like to pass in the conditions and jointPDF as variables to construct the piecewise function.

Thank you so much!

Thank you so much!

Thanks so much for helping out! This example works on my Maple 14. I will evaluate my other integrations with this approach for now. 

Thanks so much for helping out! This example works on my Maple 14. I will evaluate my other integrations with this approach for now. 

@Markiyan Hirnyk I see... 

I have a bunch of similar integrations to evaluate, and at this time I really hope i can have your maple 13.... This sounds a little bit weird and sad that the latest version couldn't handle these...

@Markiyan Hirnyk I see... 

I have a bunch of similar integrations to evaluate, and at this time I really hope i can have your maple 13.... This sounds a little bit weird and sad that the latest version couldn't handle these...

When I was trying your worksheet file in my Maple 14, it still gave me unevaluated integration. Which version is your Maple? Or is it the Maple problem? Thanks!

> evalf(int(evalf(jointPDF), op(area1)));

print(`output redirected...`); # input placeholder
   /               /               2\ /   /   /               2\ 
int\6.484555750 exp\-8.000000000 e3 / \int\exp\-8.000000000 e2 / 

  /   /   /               2\  
  \int\exp\-8.000000000 e4 / (
-0.3133285343 erf(2.828427125 e4 - 5.091168825) + 0.3133285343), 

                             \\                             \\  
  e4 = e2 + 0.900000000 .. 2.//, e2 = e3 - 1.800000000 .. 2.//, 

                \
  e3 = -2. .. 2./

When I was trying your worksheet file in my Maple 14, it still gave me unevaluated integration. Which version is your Maple? Or is it the Maple problem? Thanks!

> evalf(int(evalf(jointPDF), op(area1)));

print(`output redirected...`); # input placeholder
   /               /               2\ /   /   /               2\ 
int\6.484555750 exp\-8.000000000 e3 / \int\exp\-8.000000000 e2 / 

  /   /   /               2\  
  \int\exp\-8.000000000 e4 / (
-0.3133285343 erf(2.828427125 e4 - 5.091168825) + 0.3133285343), 

                             \\                             \\  
  e4 = e2 + 0.900000000 .. 2.//, e2 = e3 - 1.800000000 .. 2.//, 

                \
  e3 = -2. .. 2./

Thanks a lot! This works for me!

Thanks a lot! This works for me!

Thanks a lot for your help! For the PDF returned by the substitution did you mean the function was for the normal distribution (mu+t, delta) truncated at [a+t, b+t] instead of at [a, b]?  
 
Also could you explain a little bit about the math principal you used there? What if the expression X + Y where Y is a untruncated normal distribution (mu_2, delta_2), and X is still a truncated distribution (mu, delta) at [a, b], is it still possible to derive the corresponding truncated normal distribution using the same rule you mentioned? Thanks!

Thanks a lot for your help! For the PDF returned by the substitution did you mean the function was for the normal distribution (mu+t, delta) truncated at [a+t, b+t] instead of at [a, b]?  
 
Also could you explain a little bit about the math principal you used there? What if the expression X + Y where Y is a untruncated normal distribution (mu_2, delta_2), and X is still a truncated distribution (mu, delta) at [a, b], is it still possible to derive the corresponding truncated normal distribution using the same rule you mentioned? Thanks!

Thank you very much Acer! Somehow I think the default value of printbytes should be set to false instead of true... because I think normal users like me are not quite interested in those information. Is there any reason for using true as its default?

Thank you very much Acer! Somehow I think the default value of printbytes should be set to false instead of true... because I think normal users like me are not quite interested in those information. Is there any reason for using true as its default?