Or, you can use: complex(-1)**0.5
However the result is strange ... >>> complex(-1)**0.5 (6.1230317691118863e-17+1j) Pierre Danny Yoo a écrit : > > On Sat, 2 Jul 2005, Reed L. O'Brien wrote: > > >>> Does anyone know how to make Python calculate square roots? >>> >> >>Raise to the 1/2 power. >> >> >>>>>4**.5 >> >>2.0 >> >>>>>16**.5 >> >>4.0 >> >>>>>81**.5 >> >>9.0 > > > > By the way, if you need to take the square roots of negative numbers, then > the 'sqrt' function in the cmath module should do the trick: > > ###### > >>>>(-1)**0.5 > > Traceback (most recent call last): > File "<stdin>", line 1, in ? > ValueError: negative number cannot be raised to a fractional power > >>>>import cmath >>>>cmath.sqrt(-1) > > 1j > ###### > > > Best of wishes! > > _______________________________________________ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > -- Pierre Barbier de Reuille INRA - UMR Cirad/Inra/Cnrs/Univ.MontpellierII AMAP Botanique et Bio-informatique de l'Architecture des Plantes TA40/PSII, Boulevard de la Lironde 34398 MONTPELLIER CEDEX 5, France tel : (33) 4 67 61 65 77 fax : (33) 4 67 61 56 68 _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor