Alfred_F

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These are questions asked by Alfred_F

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

In the attached file, I want to transform (1) into (3) and back again (3) into (1). Attempts using CompleteSquare and expand in combination with other commands have failed. I would appreciate any advice.

dio1.mw

I recently read something in another forum about solving a simple ordinary differential equation as an initial value problem (file attached). An unexpected solution behavior was interpreted there as a weakness of the software. However, upon closer inspection, the cause is different, and as a software novice, I cannot determine it myself.

Therefore, my question is:

Is there a way, using Maple, to check the Lipschitz condition in the neighborhood of the initial value before starting the solution of an explicit first-order system of differential equations as an initial value problem?

DGL_test.mw

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