A) \[{{30}^{o}}\]
B) \[{{45}^{o}}\]
C) \[{{60}^{o}}\]
D) None of these
Correct Answer: B
Solution :
Let the line makes an angle \[\theta \] to the z-axis \[\because \] \[{{\cos }^{2}}\alpha +{{\cos }^{2}}\beta +{{\cos }^{2}}y=1\] \[\therefore \] \[{{\cos }^{2}}\,{{60}^{o}}+{{\cos }^{2}}{{60}^{o}}+{{\cos }^{2}}\theta =1\] \[\Rightarrow \] \[\frac{1}{4}+\frac{1}{4}+{{\cos }^{2}}\theta =1\] \[\Rightarrow \] \[{{\cos }^{2}}\theta =1-\frac{1}{2}=\frac{1}{2}\] \[\Rightarrow \] \[\cos \,\,\theta =\frac{1}{\sqrt{2}}\] \[\Rightarrow \] \[\theta ={{45}^{o}}\] \[\Rightarrow \]
You need to login to perform this action.
You will be redirected in
3 sec
