I have an expression for $div$ with Lame coefficients. I want to look at the $div$ in different coordinate systems. So I want to substitute the Lame coefficients not letting Mathematica to actually differentiate, thats why I am using hold. So I need a valid combination of hold and substution to get what I need. Here is my code
divA = Hold[(1/(H1*H2*H3))*(D[Ax*H2*H3, x] + D[Ay*H3*H1, y] +
D[Az*H1*H2, z])]
Hold[(D[Ax*H2*H3, x] + D[Ay*H3*H1, y] + D[Az*H1*H2, z])/(H1*H2*H3)]
divA /. {H1, H2, H3} -> {1, 1, 1}
Hold[(D[Ax*H2*H3, x] + D[Ay*H3*H1, y] + D[Az*H1*H2, z])/(H1*H2*H3)]
It is just dont substitute. Could u please help me get what I want?
{H1, H2, H3}
to replace... TrydivA /. Thread[{H1, H2, H3} -> {1, 1, 1}]
, it has nothing to do withHold
. $\endgroup$Hold[(D[Ax*1*1, x] + D[Ay*1*1, y] + D[Az*1*1, z])/(1*1*1)]
It didn't do multiplication. I want multiplication to be done but not differentiation. $\endgroup$Inactivate
onD
. $\endgroup$