Q.

The equations of the lines on which the perpendicular from the origin make 30° angle with x-axis and which form a triangle of area 503 with axes, are

1 x+3y±10=0  
2 3x+y±10=0  
3 x±3y-10=0  
4 None of the above  

Ans.

(2)

Let p be the length of perpendicular from the origin on the given line. Then its equation in normal form is given by

xcos30°+ysin30°=p  or  3x+y=2p

This meets with the coordinate axes at A(2p3,0)  and  B(0,2p).

∴  Area of ∆OAB=12(2p3)(2p)=2p23

Also, it is given that 2p23=503⇒p=±5

Hence, the required equations of the lines are 3x+y±10=0