Your package sympy failed to build from source in current rawhide. http://koji.fedoraproject.org/koji/taskinfo?taskID=7008940 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_21_Mass_Rebuild
Created attachment 906898 [details] build.log
Created attachment 906899 [details] root.log
Created attachment 906900 [details] state.log
The build failure was due to two bugs in upstream mpmath 0.19, and one packaging bug in python3-dateutil (bug 1140413). All bugs have been worked around until they can be fixed in their respective packages. Successful builds have been done for Rawhide and F-21.
sympy-0.7.5-3.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/sympy-0.7.5-3.fc21
sympy-0.7.5-4.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.