Write the structure and name of the monomer of Nylon-6.
Nylon-6 Monomer: The monomer for Nylon-6 is caprolactam.
Explain the construction of a spherical wavefront by using Huygens' principle.
The slope of the tangent to the curve \( x = \sin\theta \) and \( y = \cos 2\theta \) at \( \theta = \frac{\pi}{6} \) is ___________.