We need to find the principal value of \( \cot^{-1} \left( -\frac{1}{\sqrt{3}} \right) \).
The principal value of \( \cot^{-1}(x) \) lies in the range \( (0, \pi) \). For \( \cot \theta = -\frac{1}{\sqrt{3}} \), the corresponding angle \( \theta \) in the principal range is \( \theta = \frac{2\pi}{3} \), since \( \cot \frac{\pi}{3} = \frac{1}{\sqrt{3}} \), and \( \cot \left( \frac{2\pi}{3} \right) = -\frac{1}{\sqrt{3}} \).
Thus, the principal value of \( \cot^{-1} \left( -\frac{1}{\sqrt{3}} \right) \) is \( -\frac{2\pi}{3} \).
Determine whether each of the following relations are reflexive, symmetric, and transitive.
Show that the relation R in the set R of real numbers, defined as
R = {(a, b): a ≤ b2 } is neither reflexive nor symmetric nor transitive.
Check whether the relation R defined in the set {1, 2, 3, 4, 5, 6} as
R = {(a, b): b = a + 1} is reflexive, symmetric or transitive.