$tan(cot^{-1}x)$ is equal to

$\frac{\pi}{2}-x$ $cot(tan^{-1}x)$ tan x none of these

$cot(tan^{-1}x)$

We have  $tan(cot^{-1}x)= tan \left(\frac{\pi}{2}-tan^{-1}x\right) = cot (tan^{-1}x)$