Question

cos-1 ( cos 7π / 6 ) का मान बराबर है(A) 7π/6 (B) 5π/6 (C) π/3 (D) π/6

Answer 1

Answer:

Step-by-step explanation:

$cos^{-1}(cos(\dfrac{7\pi}{6} ))\\\\=cos^{-1}(cos(\pi+\dfrac{\pi}{6}))\\\\\\=cos^{-1}(-cos\dfrac{\pi}{6})\\\\\\=cos^{-1}(cos(\pi-\dfrac{\pi}{6}))\\\\\\=cos^{-1}(cos\dfrac{5\pi}{6}))\\\\\\=\dfrac{5\pi}{6}$

not that $\dfrac{5\pi}{6}$∈ [0,π]