12. Deduce standard equation of hyperbola. dy dx 13. Solve the differential equation: x logx+y=2logx dy 14. Solve: (x-a)p +(x-y)p-y=0: where p = dx 15. Solve: (D-D-2)y = e* + sin 2x 16. Find a current i(t) in the RLC circuit assuming zero initial current and charge q, if R = 80 ohms, L = 20 Henry, C=0.01 Fardays and E = 100 volts.