I'm attempting to solve a difference equation(adsbygoogle = window.adsbygoogle || []).push({});

y(k+1) = -0.5*y(k) + x(k)

where y(0) = 0 and x(k) is in my case a unit step function ie = 1

well, i'm trying to solve this using a for loop, but am having some trouble. The code i've generated gets an error, "Index into matrix is negative or zero."

Any ideas?

My code is below.

k = 0 ; %counter variable

y = 0; %y(k)

x = 1; %x(k), unit step function

for k = 0 : 5

y(k+1) = -.5*y(k) + x;

y(k) = y(k+1)

end

Thanks for any help.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Matlab for loop and difference equation question

**Physics Forums | Science Articles, Homework Help, Discussion**