996q 2
the straight line xcosA+ysinA =c and xsinA-ycosA=0 are mutually perpendicular .Line xcosA+ysinA=c ,is in normal form .So, the perpendicular from the origin as this line is or length c and makes angle pie/4 with X-axis .The line xsinA-ysinA=0 passes through the origin and makes angle A with x-axis .So this is perpendicular frm origin on xcosA+ysinA =c.line ax+by+c=0(pq) makes angle pie/4 with xcosA+ysinA=c and xcosA+ysinA=c n xsinA-ysinA=0 are mutually perpendicular .So,ax+by+c =0is a bisector of the angle between them.after construction oq =opsin45
also lengthof the perpendicular from (0,0)on ax+by+c=0 is c/√a^2+b^2
on equating both we get a^2+b^2=0