ARCSIN or inverse sin in MATHCAD 14 ?

  Hello, Everyone.

The question : What does the " float ---> -1.0097419586828951109e-28 " mean ? 

                and What does the " float ---> - 5.0487097934144755546e-29 " mean ?

Need help with brief explanation.

  Thanks in advance for the time and help.

     Best Regards.