Alfred_F

Mr. Alfred Flaßhaar

485 Reputation

11 Badges

1 years, 198 days
Brandenburg, Germany
As a retired individual with degrees from German universities in mathematics/analysis and structural engineering, I spent my professional life in responsible positions in research, teaching, and practical application, working on the mathematical modeling of states and processes in real-world systems. Now I have the time to explore interesting mathematical problems using Maple. It is my professional curiosity that drives me.

MaplePrimes Activity


These are questions asked by Alfred_F

According to the help text in Maple 2024.2, a number of classical integral equations can be solved using "intsolve". The Volterra equation of the first kind, with an upper limit of integration x, is of particular interest. A long time ago, I had to solve a similar equation. This one arose from a model of a real-world process, but instead of x, the upper limit of integration was the function y(x), which I had to calculate. I painstakingly solved it to a good approximation. Is there an algorithm in Maple that can at least calculate an approximate solution, or is a numerical solution, e.g., using Ritz, the only option?

edited: I forgot to upload an example

 test.mw

On my journey of discovery through the Maple world, I now want to try out Maple's convenient features in the complex plane, something that used to be laboriously worked out and demonstrated on the blackboard with chalk. I couldn't find a suitable introduction in the help text. I'm interested in whether a package needs to be loaded and how to handle polynomials, series, and line integrals (I have a reasonable understanding only of the theory).

In the attached file, I want to calculate the integral Q1. Numerically, this is easy to do in Maple. For theoretical reasons, the exact result pi/e is known. However, a contradiction arises between command lines (4) and (5). Command (6) is also unsuccessful, as its exact result is unknown. What am I doing wrong?

restart

Q1 := int(sin(Pi*x)/(x^x*(1-x)^(1-x)), x = 0 .. 1)

int(sin(Pi*x)/(x^x*(1-x)^(1-x)), x = 0 .. 1)

(1)

evalf[100](Q1)

1.155727349790921717910093183312696299120851023164415820499706535327288631840916939440188434235673559

(2)

evalf[100](Pi/exp(1))

1.155727349790921717910093183312696299120851023164415820499706535327288631840916939440188434235673559

(3)

is(Q1 = Pi/exp(1))

false

(4)

identify(evalf[100](Q1))

Pi*exp(-1)

(5)

identify(.2340257795502385151002175791580229871350403567739388325733228478980460706709848394726222465477567339)

.2340257795502385151002175791580229871350403567739388325733228478980460706709848394726222465477567339

(6)

NULL

Download test.mw

The plot in the attached file only works if the complete function expression is entered. If only the function name is entered, no plot appears. What am I doing wrong?test.mw

restart;

c(x)dsum(sin(10^k*x)/10^k, k = 1 .. 10^2)

plot(c(x), x = -(1/4)*Pi .. (1/4)*Pi)

 

``

c(x)dsum(sin(10^k*x)/10^k, k = 1 .. 10^2)

plot(sum(sin(10^k*x)/10^k, k = 1 .. 10^2), x = -(1/4)*Pi .. (1/4)*Pi)

 

 

NULL

Download test.mw

I'm looking for the general solution to the attached differential equation. Maple doesn't provide it. What am I doing wrong?

restart

ode5 := diff(y(x), x) = (8*y(x)*b-32*b^2*x/y(x)-64*b^2*x^2*y(x))/(3*y(x)^2+8*b*x-16*b^2*x^2/y(x)^2)

diff(y(x), x) = (8*y(x)*b-32*b^2*x/y(x)-64*b^2*x^2*y(x))/(3*y(x)^2+8*b*x-16*b^2*x^2/y(x)^2)

(1)

simplify(ode5)

diff(y(x), x) = ((64*b^2*x^2-8*b)*y(x)^3+32*b^2*x*y(x))/(-3*y(x)^4-8*b*x*y(x)^2+16*b^2*x^2)

(2)

dsolve(ode5, y(x))

NULLNULL

Download testdgl5.mw

1 2 3 4 5 6 7 Last Page 1 of 16