I'm attempting to differentiate an equation in the form
D[sqrt((2*(((a*b*c+Pi*d*e^2+Pi*f*g^2+h*i*j+Pi*k*l^2)/(a*b*c+Pi*d*e^2+Pi*f*g^2))-1)*m)/(n^2 - o^2)/p), a]
in order to do an error propagation analysis. So I need to differentiate it against a, against b, against c and so on.
All my values will be positive (they reflect physical dimensions of my design) and the value of n will always be greater than o.
Is there a way to define all my variables as real and positive before I differentiate? And to define n greater than o?
The best I've found is $Assumptions = _Symbol [Element] Reals but this only gets me part of the way.