Question: $2\left( \tan^{- 1}1 + \tan^{- 1}2 + \tan^{- 1}3 \right)$is equal to...

Question

$2\left( \tan^{- 1}1 + \tan^{- 1}2 + \tan^{- 1}3 \right)$ is equal to

Answer 1

The given expression is equal to

$2\left\lbrack \pi + \tan^{- 1}\frac{1 + 2}{1 - 2} + \tan^{- 1}3 \right\rbrack$

= $2\left( \pi - \tan^{- 1}3 + \tan^{- 1}3 \right) = 2\pi$

Question: \(2\left( \tan^{- 1}1 + \tan^{- 1}2 + \tan^{- 1}3 \right)\)is equal to...