Diff equation last step of the solution

  • Thread starter electron2
  • Start date
In summary, after solving a long differential question, the expression 0.5*u(t+1)-0.5*u(t-1) was obtained, where u(t) is a step function. The expression can be further developed using rectangular functions, and in order to do so, tau must be set to 2. The final solution would then be f(t)= [rect(t/2)]/2.
  • #1
electron2
46
0
after solving a long diff question i got

0.5*u(t+1)-0.5*u(t-1)

where u(t) is a step function for t>=0 its 1
and t<0 its 0

my expression looks pretty finite to me

how to continue??
 
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  • #2
electron2 said:
after solving a long diff question i got

0.5*u(t+1)-0.5*u(t-1)

where u(t) is a step function for t>=0 its 1
and t<0 its 0

my expression looks pretty finite to me

how to continue??
I don't understand the question. Does your expression form part of an equation? What is the end goal?
 
  • #3
my expression is the final solution
but i was told that it cam be developed further more

how??
 
  • #4
electron2 said:
my expression is the final solution
but i was told that it cam be developed further more

how??
You're expression cannot be the final solution since it is not an equation! What is on the left hand side of the equality sign?

However, linear combinations of heaviside (step) functions can often be written in terms of the rectangular function.
 
  • #5
believe me there is a left side
its some intergral
and its not important

how to write it in terms of the rectangular function?
 
  • #6
electron2 said:
believe me there is a left side
its some intergral
and its not important
Okay, if you say so.
electron2 said:
how to write it in terms of the rectangular function?
Try googling rectangle function.
 
  • #8
electron2 said:
i looked it in google
http://en.wikipedia.org/wiki/Rectangular_function
its not helping at all
Well you obviously didn't look hard enough since the answer is virtually given in the second equation!
electron2 said:
how to write it using rectangular functions
I'm here to help you with your work, but I'm not simply going to give you the answer.
 
  • #9
ok so look at it as if
i asked to solve the whole question
and i showed the solution till some point
and i need to finish it

by saying
"I'm here to help you with your work, but I'm not simply going to give you the answer."

you are not helping at all
you could give a hint
or a article

but you didnt
 
  • #10
electron2 said:
by saying
"I'm here to help you with your work, but I'm not simply going to give you the answer."

you are not helping at all
you could give a hint
or a article

but you didnt
I did give you a hint in post #6, which lead you to an article. I then gave you another hint in post #8, the answer is given there in the second formula on the wiki page!
 
  • #11
the formula is with (t-0.5)

and i have t-1

how to suit it with my expression
 
  • #12
electron2 said:
the formula is with (t-0.5)

and i have t-1

how to suit it with my expression
Let's have a look at the expression,

12bbbf9bd48745e67223553a4c97510d.png


And compare with your expression,

[tex]f\left(t\right) = \frac{1}{2}\left[u\left(t+1\right)-u\left(t-1\right)\right][/tex]

So, what do you have to set tau to, in order to make wiki's expression the same as yours?
 
Last edited:
  • #13
so tao=2

so its f(t)= [rect(t/2)]/2

correct?
 
  • #14
electron2 said:
so tao=2

so its f(t)= [rect(t/2)]/2

correct?
Indeed it is :approve:
 
  • #15
thanks
 

1. What is the last step in solving a differential equation?

The last step in solving a differential equation is to find the particular solution by applying any initial or boundary conditions given in the problem. This involves plugging in the values for the variables and constants and solving for the unknown function.

2. How do you know when you have reached the last step in solving a differential equation?

You know you have reached the last step in solving a differential equation when you have found the general solution and have applied any necessary initial or boundary conditions to find the particular solution. This results in a unique solution to the differential equation.

3. Can the last step in solving a differential equation be skipped?

No, the last step in solving a differential equation cannot be skipped. This step is crucial in finding a unique solution to the differential equation and is necessary to satisfy any given initial or boundary conditions.

4. Are there any shortcuts for the last step in solving a differential equation?

There are no shortcuts for the last step in solving a differential equation. However, there are certain techniques and methods, such as separation of variables or using integrating factors, that can make the process more efficient and easier to solve.

5. Is there a specific formula for the last step in solving a differential equation?

No, there is no specific formula for the last step in solving a differential equation. The particular solution is unique to each differential equation and depends on the given initial or boundary conditions. Therefore, it requires careful consideration and problem-solving skills to find the particular solution for each individual problem.

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