Q.

Which of the following equation is linear

1 dydx+xy2=1  
2 x2dydx+y=ex  
3 dydx+3y=xy2  
4 xdydx+y2=sinx  

Ans.

(2)

Ans.      x2dydx+y=ex

Explanation:

x2dydx+y=ex can be written as

dydx+yx2=exx2, which is a linear equation.