Q.

The solution of the differential equation xdy-ydx=0 represent family of:

1 Circles passing through origin  
2 Straight line passing through (−1, 6)  
3 Straight line passing through the origin  
4 Circle whose centre is at the origin  

Ans.

(3)

Ans.     Straight line passing through the origin

Explanation:

              xdy-ydx=0

                        1ydy=1xdx

On integrating both side,

                      ∫1ydy=∫1xdx

                           log y=log x+log c

                           log y=log(cx)

                                   y=cx

It is equation of straight line passing through origin.