title: Creating Sine Waves Within MatLab
body: <p>I'm trying to create a sine wave audio signal within MatLab based on this function:</p>
  
  <p><img src="https://i.stack.imgur.com/LMfTL.png" alt="Sinusoidal Functions"></p>
  
  <p>So far I have created a vector <code>x</code> that starts at <code>0</code>, increments in <code>0.1</code> to <code>10</code></p>
  
  <p>Followed by this:</p>
  
  <p><code>y = 3*sin(x(2*pi/4))+2;</code></p>
  
  <p>I have multiplied <code>x</code> by <code>2*pi/4</code> in order to resize the period to a quarter of its size, but I have errors regarding indexes being positive.</p>
  
  <p>Also, is it at all possible to actually create a signal at a specific Hz.  For example if I wanted a sine wave at 800Hz?</p>