E.R. Braithwaite, the narrator in "To Sir With Love," is a young, ambitious, and determined teacher. As a black man in a racially prejudiced society, he faces significant challenges. However, his confidence, intellect, and perseverance allow him to win the respect and trust of his students. Braithwaite is patient, empathetic, and highly skilled in dealing with the struggles of his students. Through his work and dedication, he gradually changes both the attitudes of his students and the community. His character represents growth, understanding, and the power of education.
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 ___________.