For each system in Problems 1-3, determine the dependent variable. f, given that t is the independent variable, and the parameters; determine whether the system is autonomous or nonautonomous, linear or nonlinear, and (ij linear) homogeneous or nonhomogeneous.
1. x' = x + t y
y' = 2x + y + y sin t
2. u' = 3 u + 4u
u' = -2u + sin t
3. x; = K x2
x; = - sin x1