0
623views
prove that $(\tan ^{-1}(1)+\tan ^{-1}(2)+\tan ^{-1}(3)=\pi$
1 Answer
written 5.2 years ago by |
Solution:
$\tan ^{-1}(1)+\tan ^{-1}(2)+\tan ^{-1}(3)$
$=\pi+\tan ^{-1}\left(\frac{1+2}{1-(1)(2)}\right)+\tan ^{-1}(3)$
$=\pi+\tan ^{-1}(-3)+\tan ^{-1}(3)$
$=\pi-\tan ^{-1}(3)+\tan ^{-1}(3)$
$=\pi$