Matlab wrong cube root How can I get MATLAB to calculate $(-1)^{1/3}$ as $-1$? Why is it giving me $0.5000 + 0.8660i$ as solution? I have same problem with $({-1\over0.1690})^{1/3}$ which should be negative.

Try nthroot(-1,3).
If you type (-1)^(1/3), it'll give you the solution to $x^3=-1$ on the complex plane with lower argument.
