$\cos \left(\cos ^{-1}\left(-\frac{1}{4}\right)+\sin ^{-1}\left(-\frac{1}{4}\right)\right) = $ . . . . . . .

જો $\operatorname{Tan}^{-1} \frac{1}{3}+\operatorname{Tan}^{-1} \frac{1}{7}+\operatorname{Tan}^{-1} \frac{1}{13}+\ldots+\operatorname{Tan}^{-1} \frac{1}{n^2+n+1}=\operatorname{Tan}^{-1} \theta$ હોય,તો $\theta=$

$\sin \left( {2{{\tan }^{ - 1}}\left( {\frac{1}{3}} \right)} \right) + \cos ({\tan ^{ - 1}}(2\sqrt 2 ))$ ની કિંમત શોધો.

$\tan ^{-1}\left(\frac{1}{2 \sqrt{2}}\right)+\sin ^{-1}\left(\frac{1}{\sqrt{3}}\right)=\cos ^{-1} x$ હોય, તો $x=$

ધારો કે $\tan ^{-1} y = \tan ^{-1} x + \tan ^{-1} \left( \frac{2x}{1 - x^2} \right)$,જ્યાં $|x| < \frac{1}{\sqrt{3}}$,તો $y$ ની એક કિંમત શું છે?

$\frac{d}{dx}[\tan^{-1}(\cot x) + \cot^{-1}(\tan x)] = $