I ask Sage to calculate the following expression
x = (70 - 13*sqrt(29))^(1/3) + (70 + 13*sqrt(29))^(1/3)
print x
print N(x)
I receive the following reply:
(13*sqrt(29) + 70)^(1/3) + (-13*sqrt(29) + 70)^(1/3)
5.28887360535083 + 0.166781253811029*I
But my calculator says 5. I don't understand why?
