Maple Tutor

Part 3: Variables

1. Enter
   x:=3; y:=2;
2. Enter
   2*x+y;
3. The result of the preceding step follows from the fact that the variable x has been assigned the value 3 and the variable y has been assigned the value 2. Check this by entering
   x; y;
4. Enter the following line. Note that it ends with a colon rather than a semicolon.
   z:=5:
   Now, using a semicolon, enter
   z;
   Entering a line with a colon has the same long-term effect as entering it with a semicolon, but nothing is displayed afterwards.
5. Use pencil and paper to decide what number xy² + 3z represents, and then check your answer by entering
   x*y^2+3*z;
   Use your mouse to return to the expression just entered, replace the 3 by 4, and press RETURN.
6. Suppose we want to remove the identification of x with 3. Enter
   x:='x';
   Check this by entering
   x;
   Note: You may also remove an identification with the unassign command. Using this method, you would enter
   unassign('x');
   Now remove the identifications of y with 2 and z with 5. Check by entering
   x*y*z;
   You should see
   xyz
   as the output.
7. Maple distinguishes between := and =. The first is used for definitions. The equals sign alone is used to enter equations. Check this by entering
   solve(s^2-s-1=0,s);
   (Here the s after the comma in the command tells Maple what to solve for.)

8. Enter
   2+3;
   and then
   % + 5;
   The percent sign has the value of the last quantity calculated. Check this by entering
   x*y;
   and then
   % + z;