NIELIT 2016 MAR Scientist C - Section B: 19

Question

If product of matrix $A=\begin{bmatrix}\cos^{2}\theta &\cos \theta \sin \theta \\  \cos \theta \sin \theta &\sin ^{2} \theta& \end{bmatrix}$ and $B=\begin{bmatrix}\cos^{2}\phi &\cos \phi \sin \phi \\  \cos \phi \sin \phi &\sin ^{2} \phi& \end{bmatrix}$ is a null matrix, then $\theta$ and $\phi$ differ by an

• A. odd multiple of $\pi$
• B. even multiple of $\pi$
• C. odd multiple of $\dfrac{\pi}{2}$
• D. even multiple of $\dfrac{\pi}{2}$

 

Comments

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