@tomleslie 

Works for me now too. Strange. Must have missed something. Thanks anuhow.

S

@Rouben Rostamian  

@Rouben Rostamian  

Even with your bc I can't get a solution, why?

bc2 := (D[2](u))(t, -(1/2)*Pi) = 0, (D[2](u))(t, (1/2)*Pi) = 0

pdsol3 := pdsolve({bc2, ic, pde}, u(t, x), HINT = f(x)*g(t))

This has to be something else. I've tried with language settings in Windows and so on. Doesn't help.

Thank you all for your answers!

@Markiyan Hirnyk 

@Markiyan Hirnyk 

Well if I choose an integral with limits it will look more like a times new roman font than a calibri font.

@Markiyan Hirnyk 

ok. But how about the font of palettes?

@Preben Alsholm 

Thanks for the numerical contribution. I'm totally satisfied with your first contribution but will save your last answer.

Staffan

Great. Many thanks. Have to think about that :)