let L1 be the line of intersection of the planes x-2y=5 and x+z=-1
and let L2 be the line of intersection of the planes 4x-3y=5 and , z=0 ,find the angle between L1 and L2
let L1 be the line of intersection of the planes x-2y=5 and x+z=-1
and let L2 be the line of intersection of the planes 4x-3y=5 and , z=0 ,find the angle between L1 and L2










