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2024-05-20 23:24:09 +0100 commented question is this a bug?

the gamma angle of a (3,8,7) triangle is pi/3, not 2pi/3; Sage will give both answers.

2024-05-20 23:23:14 +0100 commented question is this a bug?

I did not manage to make it show up as code, sorry, but it is code.

2024-05-20 23:22:50 +0100 edited question is this a bug?

is this a bug? sage: a 3 sage: b 8 sage: c 7 sage: t = (aa + bb - cc)/(2.0 *ab) sage: acos(t) 1.04719755119660 sage: N(a

2024-05-20 23:16:31 +0100 edited question is this a bug?

is this a bug? sage: a 3 sage: b 8 sage: c 7 sage: t = (aa + bb - cc)/(2.0 *ab) sage: acos(t) 1.04719755119660 sage: N(a

2024-05-20 23:15:18 +0100 edited question is this a bug?

is this a bug? sage: a 3 sage: b 8 sage: c 7 sage: t = (aa + bb - cc)/(2.0 *ab) sage: acos(t) 1.04719755119660 sage: N(a

2024-05-20 23:13:39 +0100 asked a question is this a bug?

is this a bug? sage: a 3 sage: b 8 sage: c 7 sage: t = (aa + bb - cc)/(2.0 *ab) sage: acos(t) 1.04719755119660 sage:

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2022-01-22 06:07:28 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2022-01-22 04:24:53 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2022-01-22 04:24:08 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2022-01-22 04:23:44 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2022-01-22 04:23:18 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2022-01-22 04:22:13 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

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2021-12-27 19:05:47 +0100 answered a question compute regulator with more precision

Someone pointed me to Maurer's dissertation: https://tuprints.ulb.tu-darmstadt.de/87/ which answers the theoretical pa

2021-12-27 03:13:04 +0100 edited question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

2021-12-27 03:10:10 +0100 asked a question compute regulator with more precision

compute regulator with more precision I want to compute the regulator of a real quadratic field Q(sqrt d) to high preci

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2016-01-22 20:54:33 +0100 commented answer wrong answer from solve?

So then, if solve returns [], that does not mean "there are no solutions". It means, "I didn't find any solutions". Similarly, if it does return a list of solutions, I guess that means "Here are the solutions I found", rather than, "Here are all the solutions." If this is the case, the documentation should say so up front. It says, "if there are no solutions it returns an empty list" but says nothing about the converse.

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2016-01-22 17:03:04 +0100 asked a question wrong answer from solve?
var('t')
test3 = -4*cos(t)^4 + 4*cos(t)^2 - 1
sage: solve(test3==0,t)
[]

When actually the equation is equivalent to (cos(t))^2 = 1/2 and it does have solutions.

2016-01-15 19:34:15 +0100 commented question can sage be made to do this algebra?

The originally posted code gave a negative result due to an extra minus sign.
The image of the results came from the code without that minus sign, so it's positive. Thanks for pointing out how to include code and images. Putting assumptions in doesn't make any difference (I did have some in but deleted them for simplicity). So the answer is, to simplify subexpressions you can cut and paste them, simplify them separately, then use substitution and a second cut-and-paste to get them substituted back in. Fine, if you are working interactively, but that doesn't work in a script. Can anyone give a script that starts with sin(4t) + sin(2t) and produces a result that is trig functions of 2*t without pre-calculating the answer (either by hand or in Sage)?

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2016-01-15 17:20:21 +0100 asked a question can sage be made to do this algebra?

Enneper's wire lies on an ellipsoid. I want to prove the curvature vector of Enneper's wire always points inward (never tangent to the ellipsoid). The plan is to show that the dot product of the curvature vector with the inward normal to the ellipse is strictly positive.

So I start like this:

  R,t = var('R,t')
    X = vector((R * cos(t) - (1/3)* R^3 * cos(3*t), 
            - R * sin(t) - (1/3) *R^3 * sin(3*t),
             R^2 *cos(2*t)))
    Xtheta = X.diff(t)
    T = 1/(abs(Xtheta)) * Xtheta   # unit tangent
    kappavector = T.diff(t) 
    EllipsoidNormal = vector((-2*R*cos(t) + (2/3)*R^3*cos(3*t),
    2*R*sin(t) + (2/3)*R^3 * sin(3*t),-(4/3)*R^2*cos(2*t)))
    test = EllipsoidNormal.dot_product(kappavector).trig_simplify()
    print(test)

So far so good.

image description

In general it is difficult to get Sage to do something to PART of a formula. For example in sin(4t) + sin(2t), get Sage to apply a double angle formula to sin(4t) so everything comes out in trig functions of 2t.

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2015-04-19 18:41:42 +0100 commented question sagetex on Mac OS 10.10.2

OK, now I have a sagetex.sty with copyright date 2012. (In case it helps anyone else, the Mac finder does not display this file buried in the Sage installation, even after specifying "show system files", which does cause the ones in (the old) Texlive to show up. Use the Unix command "locate sagetex.sty".) And I discovered that the new sagetex.sty does not generate Myfile.sage but rather Myfile.sagetex.sage. So you need to load or attach THAT file. But I'm still not home free. It seems the generated python code needs to prepend "./" to the filename. It does not do that so it can't run the generated Sage code:

-> 282 sagef = open(self.filename + '.sagetex.sage', 'r') 283 m = hashlib.md5() 284 for line in sagef:

IOError: No such file or directory