Classical frequency-domain methods – Match contributor to the associated plot/technique List I (Contributor) A. Bode B. Evans C. Nyquist List II (Technique) Asymptotic magnitude/phase plots (Bode plots) Polar plots based on encirclement criterion Root-locus technique Choose the correct mapping.

Introduction / Context:Bode plots, root locus, and Nyquist plots are cornerstone tools in classical control design. Each technique is associated with a specific historical contributor and serves a distinct purpose in assessing stability and shaping dynamics in the frequency domain.

Given Data / Assumptions:

• Bode: log-magnitude and phase plots vs. frequency with asymptotic approximations.
• Evans: root-locus method tracing closed-loop pole movement as gain varies.
• Nyquist: polar plot of open-loop response to apply the Nyquist stability criterion.

Concept / Approach:

Match name to technique: Bode ↔ asymptotic frequency plots; Evans ↔ root locus (geometry of closed-loop poles); Nyquist ↔ polar encirclement of the critical point in the complex plane to infer closed-loop stability.

Step-by-Step Solution:

Verification / Alternative check:

Any introductory control textbook or standards like ISO/IEEE tutorials confirm these canonical associations.

Why Other Options Are Wrong:

Pairing Bode with polar plots or Evans with Bode plots mixes distinct methodologies with different graphical constructions and interpretations.

Common Pitfalls:

Confusing Nyquist polar plots with Nichols charts; mistaking asymptotic Bode lines for exact frequency response (they are approximations refined near corner frequencies).

Final Answer:

A-1, B-3, C-2.