I've been able to derivate some function but not the following one:.Code:Dirac := (m dx[t])/(2 Sqrt[dx[t]^2 + dy[t]^2 + dz[t]^2])

I want to derivate the Dirac's function with respect to t. I triedbut then I getCode:D[Dirac[dx, dy, dz], t]which isn't what I'm looking for, I believe (I don't even know what this output mean). Notice that dx, dy and dz aren't the differentials x, y and z. Rather, they're functions which depends on t.Code:((m \!\(\*SuperscriptBox["dx", "\[Prime]", MultilineFunction->None]\)[t])/( 2 Sqrt[dx[t]^2 + dy[t]^2 + dz[t]^2]) - (m dx[t] (2 dx[t] \!\(\*SuperscriptBox["dx", "\[Prime]", MultilineFunction->None]\)[t] + 2 dy[t] \!\(\*SuperscriptBox["dy", "\[Prime]", MultilineFunction->None]\)[t] + 2 dz[t] \!\(\*SuperscriptBox["dz", "\[Prime]", MultilineFunction->None]\)[t]))/( 4 (dx[t]^2 + dy[t]^2 + dz[t]^2)^(3/2)))[dx, dy, dz]

Any idea?