# Signal Energy

1. Aug 18, 2010

### drkidd22

1. The problem statement, all variables and given/known data

Sketch the signal:
x(t) = 2^(-t*u(t)) over (-1 < t < 1)

3. The attempt at a solution
Attached is an excel fine with my work out. I want to know is it is correct.

#### Attached Files:

• ###### HW#1.xls
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2. Aug 19, 2010

### xcvxcvvc

It is simplest to think of this as a piecewise function
$$x(t) = \begin{cases} 1, t < 0 \\ 2^{-t}, t>0 \end{cases}$$
then
$$x(t)^2 = \begin{cases} 1, t < 0 \\ 2^{-2t}, t>0 \end{cases}$$
so when you integrate x(t)^2 from -1 to 1, it breaks apart into two integrals. One is from -1 to 0 of 1, and the other is from 0 to 1 of 2^{-2t}.