Faculty use

Transfer Functions, Poles and Stability

Reward correct mathematics, explicit units, conditions, and hypotheses, interpretation, and verification. Equivalent valid reasoning should receive credit.

Problem 1

(s+2)Y=U, so H=1/(s+2).

Problem 2

Exponentially decaying natural modes and asymptotic stability, absent cancellations or hidden dynamics.

Problem 3

Definitions should identify the equation type, dependent and independent variables, parameters, conditions, units or domain, and the hypotheses behind relating zero-state output to input and interpreting poles as system modes. Use the formulas H(s)=Y(s)/U(s); poles are roots of the denominator.

Problem 4

A strong error analysis identifies the first step that violates classification, algebra, theorem hypotheses, units, initial/boundary data, or numerical assumptions; then repairs that step and re-verifies the final result.

Problem 5

Application responses vary. Require defined variables, a compatible differential-equation model connected to switching circuits, control systems, impacts, signal processing, and transient engineering response, a complete computation, interpretation, and limitations.

Problem 6

Accept two independent checks appropriate to the task: differentiation/substitution, initial or boundary conditions, dimensional analysis, phase-line or stability evidence, residuals, step refinement, conservation/energy checks, data comparison, or a second method.

Scoring guidance

Six problems × 10 points: 5 mathematical accuracy, 2 structure/justification, 2 verification/interpretation, 1 notation and communication.

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