Find the direction cosines of the two lines which are connected by the relations l + m + n = 0 an mn - 2nl - 2lm = 0.

Find the direction cosines of the two lines which are connected by the relations l-5m+3n=0,7l^(2)+5m^(2)-3n^(2)=0

If the direction cosines of the two lines satisfy the equations l + m + n = 0,2lm + 2ln - nm = 0, then the acute angle between these lines is

Find the angle between the lines whose direction cosines are given by the equation 3l + m + 5n = 0 and 6mn - 2nl + 5lm = 0