title: Relational algebra natural join Database
body: <p>Here I have the relational algebra databases:</p>
  
  <p><img src="https://i.stack.imgur.com/U87YA.png" alt="enter image description here"></p>
  
  <p>So far I have done this:</p>
  
  <p><img src="https://i.stack.imgur.com/5CzQU.png" alt="enter image description here"></p>
  
  <p>The equations are in the first screenshot at the bottom.
  I want to know if I am missing out on something because I have a feeling I haven't done the first equation correctly.</p>