I'm trying to use Mathematica to get a numerical answer for a physics problem. I define a function $V$ as the sum of three quantities divided by vector norms:
V = (q1 / Norm[r - a] + q2 / Norm[r - b] + q3 / Norm[r - c])
where
a = {2, 4, -3}
b = {-2, 3, -5}
c = {-3, -3, -3}
r = {x, y, z}
I define a new quantity DelDotV = {D[V, x], D[V, y], D[V, z]}
Then I plug in 3, 4, 5, for x, y, and z, and 1, -2, 3 for q1, q2, and q3, respectively to get a numerical value, and I'm returned the following:
I can infer that these are derivatives of absolute value functions, but I know for a fact the answer is not {0, 0, 0}, so I'm not really looking for the derivatives of absolute value of a constant. What exactly are these and why are they there?
q1
,q2
,q3
. $\endgroup$Abs
function, whichNorm
is defined in terms of. Instead ofNorm[x]
, use the explicit formSqrt[Dot[x, x]]
. $\endgroup$