@nm @Preben Alsholm
Thank you for your comments on simplifying solutions containing trigonometric expressions and also on the problem with one of the examples in the worksheet "Improvements in solving PDE & BC in Maple 2018.1". The post has been updated, showing results obtained using the Physics Update number 73:
- solutions to PDE & BC problems that involve trigonometric functions are now automatically better simplified, as in example 4;
- example 1, under "Improved handling of piecewise, eval/diff in the given problem" has been changed so that it no longer has inconsistent boundary and initial conditions, and also so that it is more easily readable with the variables ordered as (x,t) instead of (t,x). I did keep the conditions all together, because one of the complexities that pdsolve/BC must handle is that it does not require users to enter boundary and initial conditions separately, so that the program itself must find which is which.