Let \(l,m,n\) be the direction cosines of a vector then1\(l^2+m^2=n^2\)2\(l^2+m^2+n^2=1\)3\(l^2+m^2+n^2=2\)4None of the aboveAnswer & explanation+Correct answer: option 2Well known identity \(l^{2}+m^{2}+n^{2}=1\)
