## 30 Reputation

6 years, 144 days

## Error with dsolve...

Maple 2021

Dear all,

I'm using Maple to calculate the geodesics of the Poincare' Half Plane:

restart:
with(LinearAlgebra): with(DifferentialGeometry): with(Tensor): with(Tools): with(plots):
DGsetup([x,y],M1)
g1 := evalDG(1/y^2*(dx &t dx+dy &t dy))
R1 := CurvatureTensor(g1)
K := SectionalCurvature(g1,R1,D_x,D_y)
Gamma := Christoffel(g1)
C := [x(t), y(t)]
V := GeodesicEquations(C, Gamma, t)
DE := Tools:-DGinfo(V, "CoefficientSet")

simplify(dsolve(DE, explicit))

Error, (in simplify/siderels:-simplify/siderels) specified variables must be names or functions

How can I fix this error?

Thanks, Nicola

## Differential forms with Maple...

Maple

Hello

I'm using the package DifferentialGeometry with Maple 2019. I have 2 questions whose answer I've not found in the Help section:

a) If I have a 2-form omega with d(omega)=0, how can I obtain the 1-form alpha such that d(alpha) = omega?

b) if alpha is a 1-form and X a vector field, how can I calculate alpha(X)?

Thanks Nicola

## Display long formulas...

Maple 2016

Hello,

I have a very simple problem. When Maple displays long outputs I can only see a part of them. Here there is an example

https://www.dropbox.com/s/ymp1vdsg80ewu1s/Untitled.jpeg?dl=0

On my previous versions of Maple I had a slider on the bottom of the page. How can I activate it in Maple 2016?

Thanks, Nicola

## Problem with colors...

Maple 2016

Hello

I changed the color of the background of a worksheet in black (I introduced a Table for that reason) because the white color hurts my eyes. I still have a couple of things that I'd like to modify:

1. The blinking cursor is black and is now invisible. How can I change its color?

2. The default input color is red ; i'd like to change it in white. How can I do?

Thanks Nicola

## system of linear equations...

Maple 2016

Hi,

I want to solve 2 linear equations in p[1] and p[2]

eq3 = -(1/8)*(x^2+y^2+((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)+omega[1]-omega[2])*(x^2*p[1]+2*x*y*p[2]-y^2*p[1]-((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)*p[1]+omega[1]*p[1]-omega[2]*p[1])/(y^2*x*(omega[1]-omega[2])) - P[1];
eq4 = -(1/8)*(x^2*p[1]+2*x*y*p[2]-y^2*p[1]+((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)*p[1]+omega[1]*p[1]-omega[2]*p[1])*(x^2+y^2-((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)+omega[1]-omega[2])/(y^2*(omega[1]-omega[2])*x) - P[2]

solve({eq3,eq4},{p[1],p[2]});