Background: Have written a formula for the refractive index for a glass slab (n) that depends on the variables t,a and d. Now I want to calculate for example some sort of error and I'll be needing to use partial derivatives but I can't seem to make it work with the vectors I made for my values.
Current work:
t = {0.349, 0.698, 1.221};
a = 10^-3 * {0.935, 1.110, 1.260};
d = 1.96 * 10^-3 ;
n[t_, a_, d_] = Sqrt[a^2 * Sin[t]^2 + d^2 * Sin[2*t]^2] / a;
The output from this gives me the calculated values for n in a nice and tidy vector.
My problem begins now when I want to calculate some sort of error by error propagation (http://en.wikipedia.org/wiki/Propagation_of_uncertainty#Simplification).
My shot at it has been a series of tries all closely resembling something like this:
Sqrt[{D[n[t], {{t, a, d}}]*1.7*10^-3}^2 + {D[n[a], {{t, a ,d}}]*10^-3}^2 + {10^-3}]
All I want it to do is to take the partial derivative of my function with respect to one of the variables and have it calculated at the points specified by my vectors and hopefully present it as a vector just as neatly as the function did.
First time using Mathematica, please have mercy.