Grade 12th passAnalytical Geometry
If l,m,n are direction cosines of any straight line, show that the straight lines whose direction cosines are given by the equations ul+vm+wm=0 and al^2+bm^2+cn^2=0 are a.perpendicular if u^2(b+c)+v^2(c+a)+w^2(a+b)=0 b.parallel if u^2/a+v^2/b+w^2/c=0.
If l,m,n are direction cosines of any straight line, show that the straight lines whose direction cosines are given by the equations ul+vm+wm=0 and al^2+bm^2+cn^2=0 are
a.perpendicular if u^2(b+c)+v^2(c+a)+w^2(a+b)=0
b.parallel if u^2/a+v^2/b+w^2/c=0.
