- After harvesting, rhizomes are cleaned and boiled for 40-60 minutes to remove raw odor.
- They are then sun-dried for 10-15 days to reduce moisture.
- Polishing is done by rubbing dried rhizomes to improve appearance.
- Proper curing enhances color, aroma, and storage life.
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 ___________.