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Find the principal values of the following: \[ tan^{-1} (-\sqrt3)\]

$\begin{array}{1 1} \frac{\pi}{\sqrt 3} \\ \frac{-\pi}{\sqrt 3} \\ \frac{-\pi}{3} \\ \frac{\pi}{3} \end{array} $

2 Answers

Ans : \( tan^{-1}tan \large\frac{-\pi}{3}=\large\frac{-\pi}{3} \)

 

answered Feb 22, 2013 by thanvigandhi_1
edited Mar 15, 2013 by thanvigandhi_1
 
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  • The range of the principal value of $\; tan^{-1}x$ is $\left [ \large-\frac{\pi}{2}, \large\frac{\pi}{2} \right ]$
Let $tan^{-1}-\sqrt 3 = x \Rightarrow tan (x) = -\sqrt 3$
We know that the range of the principal value of $\; tan^{-1}x$ is $\left [ \large-\frac{\pi}{2}, \large\frac{\pi}{2} \right ]$
Therefore, $tan (x) = -\sqrt 3 = - tan \large\frac{\pi}{3} z$$= tan \large\frac{-\pi}{3}$
$\Rightarrow x=\large\frac{-\pi}{3}$, where $x \;\epsilon\;$ $\left [ \large-\frac{\pi}{2}, \large\frac{\pi}{2} \right ]$
answered Mar 2, 2013 by balaji.thirumalai
edited Apr 19, 2016 by meena.p
 
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