Q44 / 125 · BITSAT 2016 · Mathematics

If $\sin \theta_{1}+\sin \theta_{2}+\sin \theta_{3}=3,$ then $\cos \theta_{1}+\cos \theta_{2}$$+\cos \theta^{3}=$

  • Correct answer
    A
    0
  • B
    1
  • C
    2
  • D
    3

Solution

Since, $\sin \theta_{1}+\sin \theta_{2}+\sin \theta_{3}=3$ $\begin{array}{ll}\therefore & \sin \theta_{1}=\sin \theta_{2}=\sin \theta_{3}=1 \Rightarrow \theta_{1}=\theta_{2}=\theta_{3}= \\ & \frac{\pi}{2} \\ \therefore & \cos \theta_{1}+\cos \theta_{2}+\cos \theta_{3}=0\end{array}$

Hence, the correct answer is option: 'A'.

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