Find the angle betwween the two straight lines whose direction `l, m, n` are given by `2l+2m-n=0 and m n+nl; +l m=0.`

Find the angle betwween the two straight lines whose direction l,m,n are given by 2l+2m-n=0 and mn+nl;+lm=0

The angle between the straight lines, whose direction cosines are given by the equations 2l+2m -n=0 and mn+nl+lm=0 , is :

Find the acute angle between the two straight lines whose direction cosines are given by l+m+n=0 and l^(2)+m^(2)-n^(2)=0

Find the angle between the line whose direction cosines are given by l+m+n=0 and 2l^(2)+2m^(2)-n^(2)-0

The angle between the lines whose directionn cosines are given by 2l-m+2n=0, lm+mn+nl=0 is

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

The angle between the lines whose direction cosines are given by the equatios l^2+m^2-n^2=0, m+n+l=0 is