I am stuck in defining a function using indexed arguments.
Let's say
V[Subscript[x, 1],Subscript[x, 2]]=5Subscript[x, 1]^2+2Subscript[x, 1] Subscript[x, 2]+Subscript[x, 2]^2
Actually, I can't figure out where to put the underscore sign of the arguments, like in
f[t_]:=2t+1