7.5 Vc(t)= 4.5e-t/1.2 V, t > 0

7.7 i0(t)= -0.5e-t/0.3 mA, t > 0

7.10 i0(t)= 2/3 e-5t A, t > 0

7.13 i(t)= 5e-7.5x105t mA, t > 0

7.20 i0(t)= 2.67e-t/3.6 mA, t > 0

7.32 V0(t)= -6 +9e-6t V, t > 0

7.42 i(t) = 5 - 2.5 e-t/10-4 mA, t > 0