12. Solve: (D2+2D+1)y=e*+x. dy 13. Solve: Solve: x2. d2y dx -2x- -4y=x. OR dx A resistance of 100 ohms, an inductance of 0.5 Henry are connected in series with a battery of 20 volts. Find the current in the circuit as a function of time. 14. What does the equation of lines 7x2+4xy+4y2 =0 become when the axes are the bisectors of the angles between them? 15. Derive the equation of hyperbola in standard form. 16. Find the foci and eccentricity of the conic x+4xy+y2-2x+2y-6=0. OR 12 Describe and sketch the graph of the conic r=- 6+2sin0