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Question: Answered & Verified by Expert
If a line makes angles of measure $\frac{\pi}{6}$ and $\frac{\pi}{3}$ with $\mathrm{X}$ and Y axes respectively, then the angle made by the line with $\mathrm{Z}$ axis is
MathematicsThree Dimensional GeometryMHT CETMHT CET 2020 (20 Oct Shift 1)
Options:
  • A $\frac{\pi}{6}$
  • B $\frac{\pi}{2}$
  • C $\cdot \frac{\pi}{4}$
  • D $\frac{\pi}{5}$
Solution:
1837 Upvotes Verified Answer
The correct answer is: $\frac{\pi}{2}$
Let the line make an angle $\theta$ with $Z$ axis.
$$
\begin{array}{l}
\therefore \cos ^{2} \frac{\pi}{6}+\cos ^{2} \frac{\pi}{3}+\cos ^{2} \theta=1 \\
\therefore \cos ^{2} \theta=1-\left(\frac{3}{4}+\frac{1}{4}\right)=0 \Rightarrow \theta=\frac{\pi}{2}
\end{array}
$$

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