$\int \frac{1+\cos 4 x}{\cot x-\tan x} d x$ is equal to

The polymer having an amide linkage is

Values of the acceleration $A$ of a particle moving in simple harmonic motion as a function of its displacement $x$ are given in the table below. The period of the motion is

$A \; (mm \; s^{-2})$	$16$	$8$	$0$	$-8$	$-16$
$x \; (mm)$	$-4$	$-2$	$0$	$2$	$4$

From the following statements,select the wrong one:

In the visible region, the dispersive powers and the mean angular deviations for crown and flint glass prisms are $\omega, \omega^{\prime}$ and $d, d^{\prime}$ respectively. The condition for obtaining dispersion without deviation, when the two prisms are combined, is:

In a saturated solution of $Mg(OH)_2$,the degree of dissociation of $Mg(OH)_2$ is $\alpha$. Find the concentration $(C)$ of $Mg(OH)_2$ if the concentration of $[OH^{-}]$ is $2$.