Inverse Trigonometric Functions
NCERT Exemplar Class 12
CBSE
Grade 12
Question:
Evaluate $\cos^{-1}\left(\cos \dfrac{7\pi}{6}\right)$.
Step-by-Step Solution
\cos(7\pi/6) = \cos(2\pi - 5\pi/6) = \cos(5\pi/6). [1.0 Mark]
Since $5\pi/6 \in [0, \pi] \Rightarrow \text{Value} = 5\pi/6$. [1.0 Mark]
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🎯 Official CBSE Marking Scheme:
Transforming angle into principal branch: 1.0 Mark
Evaluating final value $= 5\pi/6$: 1.0 Mark
Correct Answer:
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