ftn1 = Sin[s]^2 + 3 t^2 + u^5
3 t^2 + u^5 + sin[s]^2
ftn2[s_, t_, u_] := ftn1 ftn2[2, 1, 2]
3 t^2 + u^5 + Sin[s]^2
Hi there, In the above code, would somebody like to comment on how to redefine the output of ftn1 in the form ftn2[...] above. This is just a simple example, oftentimes there is a complicated output of ftn1 and one has to copy and paste for ftn2[....]. That's quite cumbersome, though works well. I am wondering how to directly define ftn2 in terms of the output of ftn1 above so that to avoid copy and paste and also ftn2 works fine. As it can be seen from above "ftn2[2, 1, 2]" fails to work. Thanks!