Q.2 Using the following given forms of u(x, y) , find the corresponding exact differential equations. Find the form of these curves. (a) u = (x-a)(b-y) (b) u = exp(xy2) Q.3 Sow that the following differential equations are exact. Find their general solution (a) ydx + xdy = 0 ; (b) cosh x cos ydx = sinh x sin ydy