Cast to float first, in the event that user entered a float.  Fix two minor typo-ish errors.
Cast to float first, in the event that user entered a float.  Fix two minor typo-ish errors.

critzo/piecewise,critzo/piecewise,critzo/piecewise,critzo/piecewise,opentechinstitute/piecewise,opentechinstitute/piecewise,opentechinstitute/piecewise,opentechinstitute/piecewise