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The energy of the signal x(n) = (-0.4)n u(n) is

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  1. 1/16 J
  2. 1/36 J
  3. 5/3 J
  4. 25/21 J

Answer (Detailed Solution Below)

Option 4 : 25/21 J
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Detailed Solution

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Concept:

Energy of signal is given by:

Calculation: We have x(n) = (-0.4)n 4(n)

E = 1 + 0.42 + 0.44 + ....

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