Matlab While loop help

Hey guys i've been sitting here for 2 hours not finding a solution. There's a population of 400 wildcats. How long will it take them to die out if every year the population is going down by 10% und at least 25. I should use a while loop. Thx in advance :)

[Jan]

As usual for question, which sound like homework: Posting a working solution is less useful than trying to assist you to solve the problem by your own. So please post, what you have tried so far and ask a specific question.

[Patrick Flach]

ok sry! for better understanding: i've only one course at university where i use Matlab, so i don't have any experience in it. the only example i'v in my sheets is this one:

x=1
while x<100
Anweisungen;
end

nevermind the language it's german. i have to use a counter and not the display function to show how much iterations it takes till the population dies out. so i know how to use the counter but i don't really know how i can express the decrease of -10% and at least 25 per year in a while loop.

[Adam]

Try to work it out in pseudo-code or simple instructions first to make sure you understand the algorithm that is needed. Then you can worry about putting it into Matlab syntax.

Answer 1

[ES]

You mean this?

 iPopulation = 400;
  iYr=1;
  while(iPopulation>25)
      iPopulation = floor(0.9*iPopulation); % = 10% decrease
      disp(['At the end of year ', num2str(iYr), ' the population is ', num2str(iPopulation)]);
      iYr = iYr+1;
  end

[Jan]

Patrick cannot provide this as his own solution now. Posting working solutions to homework questions has the disadvantage, that the user might look like he is cheating. It is better to help them to find the solution by their own.

[John D'Errico]

Posting a complete answer to a homework problem is generally to be avoided. This does not help the person asking. It just convinces them there will always be someone willing to do their work for them.

[Walter Roberson]

This is not completely correct. The population decrease should be 10 percent or 25 whichever is larger

[Patrick Flach]

yeah and thats the problem i can't solve :(

[Torsten]

Each year, iPopulation decreases by max(0.1*iPopulation,25) ...

Best wishes

Torsten.

[Patrick Flach]

Just wanted to say that i've found the solution. Thx everyone for the help :)