If f(y) = ey, g(y) = y, y > 0 and F(t) = , then
F(t) = 1 - e- t(1 + t)
F(t) = et - (1 + t)
F(t) = tet
F(t) = te- t
Let f(x) be a function satisfying f'(x) = f(x) with f(0) = 1 and g(x) be a function that satisfies f(x) + g(x) = x2. Then, the value of the integeral is
C.