Practicing Success
Practicing Success
CUET Preparation Today
| The direction cosines of a vector equally inclined to the axes \(OX,OY\) and \(OZ\) are |
\(\frac{1}{\sqrt{2}},\frac{1}{\sqrt{2}},\frac{1}{\sqrt{2}}\) \(\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}}\) \(1,1,1\) None of these |
| \(\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}}\) |
| \(\begin{aligned}l=\cos \alpha, m=\cos \alpha, n&=\cos \alpha\\ \text{Since }l^{2}+m^{2}+n^{2}&=1\\ 3\cos^{2}\alpha&=1\\ \cos^{2}\alpha &=\frac{1}{3}\\ \cos \alpha &=\pm \frac{1}{\sqrt{3}}\end{aligned}\) |
