title: Evaluate postfix notation containing square, sine, log functions in it
body: <p><a href="https://i.stack.imgur.com/nWCO3.png" rel="nofollow noreferrer">Task</a></p>
  
  <p>^^^ Please see image attached first ^^^
  We practiced how to evaluate funny arithmetic expressions like: 5+5*5 => 55+5*
  Thing I don't understand here, how to treat sines, logs and square roots?
  Thanks</p>