% _ _ _ PERCENT _ _ _ _ _ _ _ _ _ _ _ _ command

The percent sign is used to precede comments; everything from a percent to the end of the line is ignored.

examples:

df(x**3 + y,x);% This is a comment key{Return} 


     2
  3*X  


int(3*x**2,x) %This is a comment; key{Return} 

A prompt is given, waiting for the semicolon that was not detected in the comment

Statement delimiters ; and $ are not detected between a percent sign and the end of the line.