Understanding Frequency Domain Parameters.
The given diagram represents a frequency response plot, likely from Nyquist Stability Criterion or Bode Plot Analysis.
1. Sinusoidal Component \( \sin \omega_c \):
- Indicates the system's response at critical frequency \( \omega_c \).
- This often corresponds to the gain crossover frequency in a Bode plot.
2. Phase Angle \( \theta \) at \( \omega_p \):
- \( \omega_p \) is the phase crossover frequency, where phase margin is measured.
- It is a key factor in stability determination.
Thus, the correct answer is:
\[
\sin \omega_c, \quad \theta \text{ is } \omega_p
\]