Mathematical Solution for Unit Time Step Signal with Plotted Coordinates

[XuFyaN]

Homework Statement

Solvinf the unit time step equation mathematically.

Homework Equations

x(t) = u(t+1) - 2u(t) + u(t-1)

The Attempt at a Solution

How can i solve this signal mathemtically :( and using plotted signals , i couldn't understand,

here is my approach and I'm not sure it is correct,

i simply wrote the coordiantes of each signal,

u(t+1) = (-1,1)

-2ut = (0,-2)

u(t-1) = (1,1)

and then added them which give answer = '0' :(

is this the way of solving the signals ?
please help

 

[gneill]

The result should be a signal that varies with time. You've identified the important times where "interesting things" take place -- the various unit step functions change value at these times.

If you were to draw several time axes stacked one over the other and plot the individual step functions, one per time axis, you might be able to see how the functions will sum up.