Why do we have dy/dx with the regular d, and 'del y/del x' with the 'funny' d? I can easily find definitions for each expresion, but the definitions appear to be logically equivalent. However, they are informal enough that it is possible that I am not understanding the definitions properly.
Specifically, can anyone show me specific inputs for which the d/dx and del/delx operators return different outputs? And do they return functions, or values?