Which of the following are sets of linearly independent functions?
(a) x, x2, x6;
(b) 8, x, x2, 3x2 - 1;
(c) sin x, cos x;
(d) sin z, cos z, tan z;
(e) sin x, cos x, eix;
(f) sin2 x, cos2 x, 1;
(g) sin2 x, cos2 y, 1.