different result of unchanged script after restart of Matlab (symbolic)

I have a script with only the following two lines:

syms x
solve(x^2)

If this script is run as first command after starting Matlab the result is:

ans = 0
      0

After running some other commands the result of running the same and unchanged script is:

ans = 
       [1x1 empty sym]

This problem occured during a beginner's course at university. It occured on different computers all running openSuse. Clearing the workspace did not solve the issue.

My question is: Is this a bug or what exactly (other than the workspace) should be cleared or changed to get the expected (first) result?

Answer 1

[Sean de Wolski]

Whenever you run any command without assigning its output to a variable, the output is assigned to ans

>>5

>>magic(3)

If you want to store it for later, assign it to a variable rather than using the default:

>>  x = 5
>>  y = magic(3)

[Qwert]

Thank you for your answer, but it does not match my question ;). I run the script and get an answer. Then I do some other symbolic things. After that I clear the workspace and run the script again. Now the answer is different from the first.