Peroxymonosulfuric acid \( H_2SO_5 \) is a strong oxidizer, often used in wastewater treatment.
Dry ice is:
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 ___________.