11 f1(t) = 2t + 1, W[f1, f2](t) = 2t^2 + 2t + 1, f2(0) = 0.
12 f1(t) = 3t - 1, W[f1, f2](t) = -3t^2 + 2t - 3, f2(0) = 1.
13 f1(t) = t - 2, W[f1, f2](t) = (3 - 2t)e^(-2t), f2(0) = 1.
14 f1(t) = 2t - 1, W[f1, f2](t) = (2t^2 - t - 1)e^t, f2(0) = 0.
15 f1(t) = t + 1, W[f1, f2](t) = (1 + t) cos(t) - sin(t), f2(0) = 0.
16 f1(t) = 4t + 1, W[f1, f2](t) = cos(t) - (4t^2 + t) sin(t), f2(0) = 0.