Defining a Step Function: Checking for Accuracy

AI Thread Summary
The discussion focuses on defining a step function using the Heaviside unit step function, u(t). The initial definition presented is C[-u(t) + u(-t)], but concerns are raised about its accuracy, particularly regarding the behavior at t = 0. It is noted that the function should be expressed in terms of u(t) for engineering purposes, and the proposed definition may not hold for all values of t. An alternative definition, C[1-2u_c(t)], is suggested as it appears to work for all real numbers. The conversation emphasizes the need for clarity in defining step functions in engineering contexts.
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I just want to check if I got this right.
Given this graph, I need to define a step function:
Code:
         |
---------| C
         |
_________|_______________
         |
      -C |_________
         |

So, my definition is: C[-u(t) + u(-t)].
Thanks for checking this.
 
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f(x) = {c, x < 0}{-c, x > 0}, f(x) is undef at x = 0, though, |f(0)| = c
 
Thanks for reply.

I understand the form of the function, but this is for an engineering class, so we have to express everything in terms of u(t), etc. So, this is what I need for some-one to double check.
And they actually never say that there is a discontinuity at 0, because we have to find values for t >=0 and so on.
 
I don't think your definition will work so well. Let's say 0<c, and 0<t<c. What is the value of your function? well u_c(t)=0 \mbox{ for } t&lt;c \mbox{ and } u_c(-t)=0 \mbox{ for } t&lt;c since t will just be negative it will still be less than c. So your function will not work in that case. I just worked from left to right to construct the definiton and came up with
C[1-2u_c(t)]

Which seems to work for all t in R.

Regards
 
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