Q.

The solution of differential equation xdy-ydx=0 represents:

1 a rectangular hyperbola  
2 parabola whose vertex is at origin  
3 straight line passing through origin  
4 a circle whose centre is at origin  

Ans.

(3)

Ans.        straight line passing through origin

Explanation:

Given that,

                 xdy-ydx=0

⇒                     xdy=ydx

⇒                     dyy=dxx

On integrating both sides, we get

                            logy=logx+logC

⇒                     logy=log Cx

⇒                           y=Cx

which is a straight line passing through origin.