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.Thu, 21 Aug 2014 03:13:28 +0200Simplification of atanhttps://ask.sagemath.org/question/23869/simplification-of-atan/ I'm teaching a course on dynamical systems based on the book by Devaney. Today I tried to show the map $f(\theta)=2\theta$ on the circle using Sage, where $\theta$ is given in radians. I could not find functions already defined to perform addition in $\mathbb{R}$ modulo $2\pi$, so I tried to devise my own. I stumbled upon this problem:
atan(sin(1/5*pi)/cos(1/5*pi))
produces
arctan(4*sin(1/5*pi)/(sqrt(5) + 1)).
Is there a way to obtain `1/5*pi`?
(By the way, _.simplify() does nothing in this case.)
RafaelThu, 21 Aug 2014 03:13:28 +0200https://ask.sagemath.org/question/23869/Is there a reasonable way to plot arcsec (real) without having a line connecting the branches?https://ask.sagemath.org/question/9104/is-there-a-reasonable-way-to-plot-arcsec-real-without-having-a-line-connecting-the-branches/I'm working on a student exploration of inverse trig functions (interact), and I'd like to plot y=arcsec(x), say from -8 to 8, without having to specify the domain. How do I turn off the spurious line that Sage draws?dasmith88Fri, 22 Jun 2012 13:40:52 +0200https://ask.sagemath.org/question/9104/Arctan(tan(2pi/3))https://ask.sagemath.org/question/8484/arctantan2pi3/i know it looks like the short cut is applicable here. But isn't there a second point on the unit circle with the same tangent as 2pi/3?
**Tan(2pi/3)= -(Sqr.rt. 3)**
There are other places with the same value for tangent. 5pi/3
**Tan(5pi/3)= -(Sqr.rt. 3)**BakesWed, 16 Nov 2011 20:54:41 +0100https://ask.sagemath.org/question/8484/