Inverse Trigonometric Functions
Xam Idea
CBSE
Grade 12
Question:
The value of $\cos^{-1}\left(\cos \dfrac{7\pi}{6}\right)$ is:
(a) $5\pi/6$
(b) $7\pi/6$
(c) $\pi/6$
(d) $3\pi/2$
Step-by-Step Solution
Key Concept: cos(7\pi/6) = cos(2\pi - 5\pi/6) = cos(5\pi/6). Since 5\pi/6 in [0, \pi], ans is 5\pi/6.
The detailed step-by-step mathematical proof is available inside the Mathbee app workspace.
Correct Answer: $5\pi/6$
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