Exercise 10.2.3

Continuation of 10.1.5. Now compute $u'(0) - u'(1)$ for the three values of $\epsilon$.

for epsilon in [0.2, 0.02, 0.002]
  x, u, du_dx = FNC.shoot(phi, (a,b), g1, g2, [-1.0, 0.0]);
  @show du_dx[1] - du_dx[end]
end