Transform the following initial-value problems into sets of first-order differential equations with appropriate initial conditions:

(a) (b) (c) (d) (f) dr dx x(1)=2, (1) = 0.5 dx dx +1- dr dr dx dr + 4(x - 1)/ = 0, dx dr x(1) = 1, d.x x(0) = 1, (0) = 2, dx dr dx dr + x(0) dx dt 1/2 -x+ -(0) = 0, -