title: How to solve for the impulse response using a differential equation?
body: <p>Given a differential equation:
  <code>y[n] - 0.9y[n-1] + 0.81y[n-2] = x[n] - x[n-2]</code></p>
  
  <p>a. Find the impulse response for <code>h[n], n=0,1,2</code> using recursion.</p>
  
  <p>b. Find the impulse response using MATLAB command filter.</p>