Integration: what am I doing wrong?

Hi all. I am (very) new to Matlab, so apologies if this is obvious:

I am trying to get to grips with symbolic integration in Matlab. I've tried a few very simple examples, and they've worked. Then I decided to try using Matlab to find the convolution of a normal p.d.f. with a half-normal p.d.f. I know that there is a closed-form solution to this integral - it should give the p.d.f. of a skew-normal r.v. - but either Matlab cannot find it or (more likely) I am missing something here. Here is the code:

syms o p u real positive
syms a real
int(1/o*normpdf((a+u)/o)*2/p*normpdf(u/p),u)

Note that, to get the skew-normal p.d.f. I actually be asking for the definite integral over 0-inf, but for now I'm just trying to get out the indefinite integral.

Answer 1

[KSSV]

syms o p u a real
k = int(1/o*normpdf((a+u)/o)*2/p*normpdf(u/p),u)

It is working fine....error is with positive variable name

[Alex Stead]

Hi KSSV,

Thanks, but that code isn't working for me. I'm using version R2013a, and still getting the "Warning: Explicit integral could not be found." message.