I define the function:
w[q_, n_, a_] := q/(4 Pi n r^2) (1 - Exp[-2 r/a] (2 (r/a)^2 + 2 (r/a) + 1))
I then want to solve:
q = 1.6*10^(-19);
n = 8.85*10^(-12);
a = 0.529*10^(-10);
Solve[w[q, n, a] == 1000, r]
This does not work and I do not understand why. I think there is a solution. Any ideas?