The number of possible enantiomeric pairs that can be produced during mono-chlorination of $2$-methylbutane is

$ \int \frac{\sin 2x}{\sin^2 x + 2\cos^2 x} dx = $

In which of the following are vessels and companion cells found?

The binomial coefficients which are in decreasing order are

If $\theta = \frac{\pi}{6}$,then the $10^{th}$ term of the series $1 + (\cos \theta + i \sin \theta) + (\cos \theta + i \sin \theta)^2 + (\cos \theta + i \sin \theta)^3 + \dots$ is equal to:

The time period of a particle in simple harmonic motion is $8 \ s$. At $t=0$,it is at the mean position. The ratio of the distances travelled by it in the first and second seconds is