The equation to the pair of lines perpendicular to the lines represented by the equation x2+4xy+2y2=0and passing through origin is 2x2+kxy+y2=0 then k =

The combined equation of pair of lines which are perpendicular to the pair of lines ax2+2hxy+by2=0and passing through the origin is bx2−2hxy+ay2=0Hence, the combined equation of perpendicular lines to the lines represented by the equation x2+4xy+2y2=0 is 2x2−4xy+y2=0.Therefore, k=−4