Impulse Sampling Property

Correct Answer

B — δ (t) 2 2 –1 –3

Concept and Reasoning

Use f(t)δ(t)=f(0)δ(t). Here f(0)=e⁰ cos(−60°)=1×1/2=1/2, so the expression equals (1/2)δ(t), which is option B.

Calculation / Key Relation

f(t)δ(t)=f(0)δ(t) → (1/2)δ(t)

Exam Takeaway

When multiplied by δ(t), evaluate the multiplying function at t=0.

Common Mistake

Do not integrate or differentiate unnecessarily; this is a direct sampling-property question.