10. Solve any three of the following differential equations. a) x dy-y dx = x + y.dx dy b) x + y.log y = xy.ex dx c) y 2px+ap2y=0 d) (D2 3D+2)y = e* 2 1.1. If the axes be turned through an angle tan0 = 2. What does the equation 4xy - 3x = a becomes? 12. Find the equation of an ellipse in the standard form. 13. If e, and e, are the eccentricities of the hyperbola, and it conjugate respectively. Then prove that + 1 2 ej =1.