If the direction cosines of two lines given by the equations `p m+qn+rl=0 and lm+mn+nl=0`, prove that the lines are parallel if `p^2+q^2+r^2=2(pq+qr+rp)` and perpendicular if `pq+qr+rp=0`

The direction cosines of two lines are given by the equations 3m+n+5l=0, 6nl-2lm+5mn=0. find the angle between them

If the direction ratio of two lines are given by 3lm-4ln+mn=0 and l+2m+3n=0 , then the angle between the lines, is

The direction cosines l, m and n of two lines are connected by the relations l+m+n=0 and lm=0 , then the angle between the lines is

The direction cosines of two lines satisfy 2l+2m-n=0 and lm+mn+nl=0 . The angle between these lines is

Prove that the lines whose direction cosines are given by the equations l+m+n=0 and 3lm-5mn+2nl=0 are mutually perpendicular.

An angle between the lines whose direction cosines are given by the equations, 1+ 3m + 5n =0 and 5 lm - 2m n + 6 nl =0, is :

The direction cosines of two lines satisfying the conditions l + m + n = 0 and 3lm - 5mn + 2nl = 0 where l, m, n are the direction cosines. The value of lm+mn + nl is

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

Prove that the two lines whose direction cosines are given by the relations pl+qm+rn=0 and al^2+bm^2+cn^2=0 are perpendicular if p^2(b+c)+q^2(c+a)+r^2(a+b)=0 and parallel if p^2/a+q^2/b+r^2/c=0

The direction cosines of two lines satisfying the conditions l + m + n = 0 and 3lm - 5mn + 2nl = 0 where l, m, n are the direction cosines. Angle between the lines is