For m,n∈N, if limx→0xn−(sinx)mxm=L, where L=n6, then m−n=
If the diagonals of the quadrilateral formed by the lines l−1x+m1y+n1=0,l2x+m2y+n2=0,l1x+m1y+n′1=0 and (l2x+m2y+n′2=0are perpendicular,then write the value of l21−l22+m2−m22
If the lines lx+my+n=0, mx+ny+l=0 and nx+ly+m=0 are concurrent then (l,m,n≠0)