If the lines joining the origin to the intersection of the line y=mx+2 and the curve x2+y2=1 ae at right angles, then

Joint equation of the lines joining the origin and the point of intersection of the line y=mx+2 and thecurve x2+y2=1 isx2+y2=y−mx22⇒ x24−m2+2mxy+3y2=0Since these lines are at right angles4−m2+3=0 ⇒m2=7