Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I have the below discrete-time system:

$$k_{i+1}= max (0, 2-k_i)$$ With $$k(0)=4$$

The state of the system keep switching between $-2$ and $0$ or i made something wrong?

share|improve this question
    
The maximum of $0$ and $-2$ is not going to be $-2$. –  Gerry Myerson Feb 3 '13 at 23:22
1  
if you replace -2 by 2 then yes. I don't mean to be unpleasant, but this is really so straightforward that I can't think OP has really put some thought into this before asking. –  Glougloubarbaki Feb 3 '13 at 23:28
    
I don't understand it. If $k(0)=4$ isn't suppose to calculate $2-k(0)= -2$ ? –  xkrpz Feb 3 '13 at 23:35
1  
no, since -2<0, you have max(0,-2)=0=k_1. Then k_2 = max(0, 2-0)=2. Then k_3 = max(0, 2 - 2)=0, etc, so it oscillates between 0 and 2 –  Glougloubarbaki Feb 3 '13 at 23:43
1  
Good. Now that you get it, you can post what you have figured out as an answer. Then, later, you can accept it. –  Gerry Myerson Feb 5 '13 at 3:58

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.