Does anybody know of a way to extract derivatives of a specified function from an expression? For example, if I have the expression,
int(D(F)(x,t,y(x,t),diff(y(x,t),x),diff(y(x,t),t),diff(diff(y(x,t),t),x))*diff(diff(yv(x,t),t),x),t = t1 .. t2);
I'd like to be able to get the derivatives of yv(x,t) which in this case would be,
I ask because I'm trying to systematically integrate a set of expressions by parts where I know that the dv term always contains a certain function's derivatives and I can stop integrating by parts once I have just the function. I know that if I use
indets(expr,specfunc(anything,yv)), I can check to see if the function is there but I'd like to know what derivatives of the function are there.