ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 28 Dec 2018 04:04:18 +0100Why doesn't assume(x, 'real') exclude complex values when using plot(x^(1/3)) over a negative domain?https://ask.sagemath.org/question/44798/why-doesnt-assumex-real-exclude-complex-values-when-using-plotx13-over-a-negative-domain/ Running the following commands:
assume(x,'real')
plot(x^(1/3), -5, 5)
produces the following error:
verbose 0 (3630: plot.py, generate_plot_points) WARNING: When plotting, failed to evaluate function at 100 points.
verbose 0 (3630: plot.py, generate_plot_points) Last error message: 'negative number cannot be raised to a fractional power'
Shouldn't the assume command take care of this?
Thanks.
douglas.y.youngFri, 28 Dec 2018 04:04:18 +0100https://ask.sagemath.org/question/44798/plots of complex numbershttps://ask.sagemath.org/question/40831/plots-of-complex-numbers/Say I want to plot the 6 solutions of [the following complex equation](https://sagecell.sagemath.org/?z=eJwrSyzSUK9S1-TlKs7PKS3JzM8rVlCwVQByylIVNKrizGxtdS10FKqACtLyixQyFTLzFIoS89JTNQx0zDSteLkUgKA4I79cA64_OjNWEwBzHBo2&lang=sage).
What is the best practice?
**EDIT** by @tmonteil: to lower dependency between Sage services in the long term, here is the code provided in the sagecell:
var('z')
solutions = solve (z^6==-8, z)
for i in range(0,6):
show(solutions[i])BostonSun, 28 Jan 2018 23:20:47 +0100https://ask.sagemath.org/question/40831/