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Question: Answered & Verified by Expert
If $\theta$ is the angle between the vectors is $4(\hat{i}-\hat{k})$ and $\hat{i}+\hat{j}+\hat{k}$, then what is $(\sin \theta+\cos \theta)$ equal to ?
MathematicsVector AlgebraNDANDA 2013 (Phase 1)
Options:
  • A 0
  • B $\frac{1}{2}$
  • C 1
  • D 2
Solution:
1102 Upvotes Verified Answer
The correct answer is: 1
Angle $\mathrm{b} / \mathrm{w}$ the vectors is $\cos \theta=\frac{4(1)-4(1)}{\sqrt{32} \sqrt{3}}=0$
$\Rightarrow \theta=\frac{\pi}{2}$
Hence, $\cos \theta+\sin \theta=\cos \frac{\pi}{2}+\sin \frac{\pi}{2}=0+1=1$.

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