Expand the following idea with the help of the points given below (100 to 150 words):
'Manners Maketh Man'
Essential Virtues
- Politeness
- Speech, tone, gestures, and action
- To be courteous and amiable
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 ___________.