a(x) = 1
b(x) = 2 x
A = (1.42, 0.38)
text1: "Equation différentielle
 a(x) y' + b(x) y=0, 
avec la condition initiale
y(" + (x(A)) + ") = " + (y(A))
g = Integral(-b(x) / a(x))
f(x) = y(A) exp(g(x) - g(x(A)))
list1 = Sequence(Sequence[Vector[(i, j), (i + 0.1 / sqrt(1 + (b(i) j / a(i))^(2)), j - 0.1 b(i) / a(i) j / sqrt(1 + (b(i) j / a(i))^(2)))], i, -3, 3, 0.2], j, -4, 4, 0.2)