Using part of output of an expression as a input of another expression
Subject: Using part of output of an expression as a input of another expression
From: Martin Schönecker
Date: Thu, 07 Jan 2010 09:55:22 +0100
Cuneyt Ertal schrieb:
...
> (%o11)
> (sum(('diff(w[n](t),t,2))*sin(%pi*n*x),n,0,inf))+%pi^4*sum(n^4*w[n](t)*sin(%pi*n*x),n,0,inf)=sum(f[n](t)*sin(%pi*n*x),n,0,inf)
>
> i want to use %o11 without sums , like this;
>
> 'diff(w[n](t),t,2)*sin(%pi*n*x)+%pi^4*(n^4*w[n](t)*sin(%pi*n*x)=f[n](t)*sin(%pi*n*x)
>
> How can I do that?
one way to do it:
(%i1) kill(all);
(%o0) done
(%i1) expr:
(sum(('diff(w[n](t),t,2))*sin(%pi*n*x),n,0,inf))+%pi^4*sum(n^4*w[n](t)*sin(%pi*n*x),n,0,inf)=sum(f[n](t)*sin(%pi*n*x),n,0,inf);
(%o1)
(sum(('diff(w[n](t),t,2))*sin(%pi*n*x),n,0,inf))+%pi^4*sum(n^4*w[n](t)*sin(%pi*n*x),n,0,inf)=sum(f[n](t)*sin(%pi*n*x),n,0,inf)
(%i2) load('opsubst);
(%o2)
C:/Programme/Maxima-5.20.1/share/maxima/5.20.1/share/contrib/opsubst.lisp
(%i3) opsubst('sum = lambda([[e]], first(e)), expr);
(%o3)
('diff(w[n](t),t,2))*sin(%pi*n*x)+%pi^4*n^4*w[n](t)*sin(%pi*n*x)=f[n](t)*sin(%pi*n*x)
Martin