If $x+iy = \frac{1+7i}{(2-i)^2}$,then $\operatorname{cosec}\left(\tan^{-1} \frac{y}{x} - \frac{\pi}{4}\right) = $

Assume that $3.13 \leq \pi \leq 3.15$. The integer closest to the value of $\sin ^{-1}(\sin 1 \cos 4+\cos 1 \sin 4)$,where $1$ and $4$ appearing in $\sin$ and $\cos$ are given in radians,is

If $y = \tan^{-1} \left( \frac{\ln(e/x^2)}{\ln(ex^2)} \right) + \tan^{-1} \left( \frac{3 + 2 \ln x}{1 - 6 \ln x} \right)$,then $\frac{d^2y}{dx^2} =$

If $x=\cos ^{-1}\left(\frac{1}{\sqrt{1+t^2}}\right)$ and $y=\sin ^{-1}\left(\frac{t}{\sqrt{1+t^2}}\right)$,then $\frac{dy}{dx}$ is

If $0 \leq x < \frac{3}{4}$, then the number of values of $x$ satisfying the equation $\operatorname{Tan}^{-1}(2x-1) + \operatorname{Tan}^{-1}(2x) = \operatorname{Tan}^{-1}(4x) - \operatorname{Tan}^{-1}(2x+1)$ is:

If $\tan ^{-1}(x+1)+\tan ^{-1} x+\tan ^{-1}(x-1)=\tan ^{-1} 3$,then for $x < 0$ the value of $500 x^4+270 x^2+997=$