Which of the following is a cyclic phosphate?

Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be:

The final product $(III)$ obtained in the reaction sequence:
$CH_3CH_2COOH$ $\xrightarrow{PCl_3} I$ $\xrightarrow[AlCl_3]{C_6H_6} II$ $\xrightarrow[base, heat]{NH_2NH_2} III$ is

Two trains travelling on the same track are approaching each other with equal speeds of $40\, m/s$. The drivers of the trains begin to decelerate simultaneously when they are just $2.0\, km$ apart. Assuming the decelerations to be uniform and equal,the value of the deceleration to barely avoid collision should be.........$m/s^2$.

If $x^3 + y^3 - 3axy = 0$,then $\frac{dy}{dx}$ equals

$\int_0^1 \sin \left(2 \tan ^{-1} \sqrt{\frac{1+x}{1-x}}\right) d x$ is equal to :