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2023-12-01 09:57:43 +0200 received badge  Nice Answer (source)
2023-12-01 07:31:10 +0200 answered a question Was not able to correctly evaluate the polynomial with roots of unity

If you need exact results, you can use: x = PolynomialRing(QQbar, 'x').gen() f = x^4 + 1 rs = f.roots(ring=QQbar,multip

2023-11-30 09:48:51 +0200 answered a question Overflow in list_plot?

Use: l = [1.4312706585e12, -1.4575266189e12, 4.9459419278e11, -4.8146621292e12] list_plot(l,frame=True)

2023-11-29 16:26:36 +0200 edited answer Plotting a Möbius transformation

This version looks nicer: complex_plot((3 * x + 7) / (-3 * x - 9), (-4,-1.5), (-1,1), contoured=True,plot_points=30

2023-11-29 15:19:40 +0200 answered a question Plotting a Möbius transformation

This version looks nicer: complex_plot((3 * x + 7) / (-3 * x - 9), (-4,-1.5), (-1,1), contoured=True,plot_points=30

2023-11-26 13:56:57 +0200 commented answer How to express (-t^2 + x^2 + y^2 + z^2) as (x_μ)^2 ?

A more compact introduction of squared metric is: M = Manifold(4, 'M') X.<t,x,y,z> = M.chart() g = M.lorentzian_m

2023-11-26 11:29:26 +0200 answered a question How to express (-t^2 + x^2 + y^2 + z^2) as (x_μ)^2 ?

Make the following modification: %display latex M = Manifold(4, 'M', latex_name=r'\mathcal{M}', structure='Lorentzian')

2023-11-25 16:47:11 +0200 answered a question differential (1-form) simplifies a bit too much

This version works better: %display latex M = Manifold(4, 'M', latex_name=r'\mathcal{M}', structure='Lorentzian') X.<

2023-11-21 16:35:20 +0200 commented answer Calculating very complex probability equation

Using numerical computations with 100 decimals precision in GP/Pari one can check that the product A is equal 0.9999999

2023-11-21 16:34:51 +0200 commented answer Calculating very complex probability equation

Using numerical computations with 100 decimals precision in GP/Pari one ca check that the product A is equal 0.99999999

2023-10-16 14:27:04 +0200 commented question Strange behaviour of `region_plot`

On the unit disc g can be replaced by g = u + abs (1 - u**2 - v**2)**(3/2) and this version should work on older versio

2023-10-06 19:36:57 +0200 answered a question Cauchy principal value integral

Also: from sympy import Integral from sympy.abc import x Integral(1/x, (x, -1, 1)).principal_value()

2023-10-02 17:35:52 +0200 answered a question Plotting a set of R^2 using three variables

Some workaround: E = EuclideanSpace(3) cylindrical.<rh,ph,z> = E.cylindrical_coordinates() cartesian.<x,y,z>

2023-09-30 23:33:05 +0200 received badge  Nice Answer (source)
2023-08-20 10:54:42 +0200 commented question max_symbolic with assumptions?

Using python from sage distribution (and full path to sage) $ ../sage/sage -python Untitled1.py one can execute the

2023-08-17 10:14:04 +0200 commented question max_symbolic with assumptions?

Using giac: giac('assume(x>0);assume(y>0);assume(y>x)'); giac('max(19*x,20*y)') 20*y

2023-08-17 10:12:37 +0200 commented question max_symbolic with assumptions?

giac('assume(x>0);assume(y>0);assume(y>x)'); giac('max(19x,20y)') 20*y

2023-08-13 11:56:54 +0200 edited answer Plot spines show in middle of graph

Some way to make them go is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.size'

2023-08-13 11:22:31 +0200 edited answer Plot spines show in middle of graph

Some way to make them go is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.size'

2023-08-13 07:37:27 +0200 edited answer Plot spines show in middle of graph

Some way to make them go is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.size'

2023-08-13 07:19:21 +0200 edited answer Plot spines show in middle of graph

Some way to make them go is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.size'

2023-08-13 07:15:23 +0200 answered a question Plot spines show in middle of graph

Some way to make them go is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.size'

2023-08-13 06:42:14 +0200 answered a question Plot spines show in middle of graph

Some way to make them go away is: from matplotlib import rcParams rcParams['xtick.major.size'] = rcParams['xtick.minor.

2023-08-02 16:14:03 +0200 commented question Displaying a matrix with scalar fields

If you accept arguments, then try matrix(3,3,lambda i,j: mymatrix[i,j].expr())

2023-08-02 16:13:40 +0200 commented question Displaying a matrix with scalar fields

If you accept arguments, the try matrix(3,3,lambda i,j: mymatrix[i,j].expr())

2023-08-02 11:33:57 +0200 commented question Taylor expansion, powers of x-a

The linear part can be rewritten as follows maxima('taylor(4/3*x + 2/3*y + 1/3,[x,1,1],[y,2,1])') ((2*(y-2))/3+3)+(4*(

2023-07-24 19:49:11 +0200 commented question how can I find the distance between a point and a polyhedron?

When x is defined as [x_0,...,x_9] (no dots) the polynomial f can be computed but frank_wolfe remains unevaluated

2023-07-24 19:48:01 +0200 commented question how can I find the distance between a point and a polyhedron?

When x is replaced by [x_0,...,x_9] the polynomial f can be computed but frank_wolfe remains unevaluated

2023-07-24 19:41:56 +0200 commented question how can I find the distance between a point and a polyhedron?

When x is replaced by [x_0,...,x_9] the polynomial f can be computed by frank_wolfe remains unevaluated

2023-07-20 11:04:31 +0200 commented question how to adjust intensity range in density_plot()

A workaround: cmap='jet'

2023-07-19 18:46:14 +0200 commented question arrow size in 3d curve plots

The color can be changed as follows: var('x,y,z,r,t') L = [(2*cos(t+pi/4),2*sin(t+pi/4), 4*sin(t+pi/4)^2) for t i

2023-07-16 08:26:17 +0200 answered a question Question for formatted output

After t=var('t') g(t)=t^2 you can diff(g(t),t) or diff(g,t)(t) Also: g=t^2 diff(g,t)

2023-07-15 18:19:54 +0200 received badge  Good Answer (source)
2023-07-15 12:17:55 +0200 commented question how can I find the distance between a point and a polyhedron?

Check https://www-fourier.ujf-grenoble.fr/~parisse/giac/cascmd_en.pdf, page 421. Giac is shipped with sage

2023-07-13 21:47:21 +0200 commented question arrow size in 3d curve plots

In line3d(... arrow_head = True,...) try radius=0.02 (for example).

2023-07-12 10:59:08 +0200 received badge  Nice Answer (source)
2023-07-11 15:26:53 +0200 answered a question Multiplication of tensor elements

Try this version: reset() Man=Manifold(4, 'Man', r'\mathcal{M}') BL.<t,r,th,ph> = Man.chart(r't r:(0,+oo) th:(0,p

2023-07-11 13:16:49 +0200 commented question Multiplication of tensor elements

The problem is that SageManifolds and canonicalize_radical make different choice of square root. I think that your meth

2023-07-10 13:33:14 +0200 edited answer Power series with alternating exponent

One way is: var('k') assume(x>-1) assume(x<1) (4*sum(x^(2*k), k, 0, oo)+sum(x^(2*k+1), k, 0, oo)/4).combine() -1

2023-07-10 13:18:13 +0200 edited answer Power series with alternating exponent

One way is: var('k') assume(x>-1) assume(x<1) (4*sum(x^(2*k), k, 0, oo)+sum(x^(2*k+1), k, 0, oo)/4).combine() -1

2023-07-10 13:16:54 +0200 edited answer Power series with alternating exponent

One way is: var('k') assume(x>-1) assume(x<1) (4*sum(x^(2*k), k, 0, oo)+sum(x^(2*k+1), k, 0, oo)/4).combine() -1

2023-07-09 21:19:38 +0200 answered a question Power series with alternating exponent

One way is: var('k') assume(x>-1) assume(x<1) (4*sum(x^(2*k), k, 0, oo)+sum(x^(2*k+1), k, 0, oo)/4).combine() -1

2023-07-09 19:18:52 +0200 received badge  Nice Answer (source)
2023-07-09 16:33:03 +0200 received badge  Nice Answer (source)
2023-07-09 15:17:14 +0200 edited answer Compute power series

For example giac('normal(sum((1+(-1)^k)*x^k,k,0,inf))').sage() -2/(x^2 - 1)

2023-07-09 15:04:13 +0200 answered a question Compute power series

For example var('k x') giac('normal(sum((1+(-1)^k)*x^k,k,0,inf))').sage() -2/(x^2 - 1)

2023-07-09 12:01:32 +0200 commented question Multiplication of tensor elements

The problem is that SageManifolds and canonicalize_radical make different choice of square root. I think that your meth

2023-07-09 11:10:16 +0200 commented question Multiplication of tensor elements

Notice that canonicalize_radical is not always right. In this case the sign of H is needed to simplify. What is worse, S

2023-07-09 10:41:45 +0200 commented question Multiplication of tensor elements

canonicalize_radical is not always right. In this case the sign of H is needed to simplify. What is worse, sage is not g

2023-07-09 10:39:50 +0200 commented question Multiplication of tensor elements

canonicalize_radical is not always right. In this case the sign of H is needed to simplify. What is worse, sage is not g