mehdi jafari

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These are questions asked by mehdi jafari

fractional Fourier transform...

Asked: mehdi jafari 749 Product: Maple

April 10 2023

1 0

Hi, i want to calculate fourier transform of functions with fractional powers. how can i do this? for example what is fourier transform of sqrt(x) ? I want a function or an expression as output, not the inetgral itself. thnx in advance

>	restart:with(inttrans):

>	f := x -> x^(1/2); int(f(x)exp(-Iw*x), x = -infinity .. infinity);

int(x^(1/2)*exp(-I*w*x), x = -infinity .. infinity)

(1)

>	fourier(f(x),x,w)

(2)

Download fracfourier.mw

dsolve an ode with parametric boundary...

Asked: mehdi jafari 749 Product: Maple 2022

February 13 2023

1 0

i have on ode with some parameters. it is ok and it is solved. but when i substitute the parameter itself, it is not solved, can i use any assumption to solve this? tnx for the help.

diff(diff(T(x), x), x)+q/k = 0

(1)

(2)

(3)

T(x) = -(1/2)*q*x^2/k-(1/40)*h[1]*(800*k*T[inf1]*h[2]-800*k*T[inf2]*h[2]-40*k*q-q*h[2])*x/((20*k*h[1]+20*k*h[2]+h[1]*h[2])*k)+(1/40)*(800*k*T[inf1]*h[1]+800*k*T[inf2]*h[2]+40*T[inf1]*h[1]*h[2]+40*k*q+q*h[2])/(20*k*h[1]+20*k*h[2]+h[1]*h[2])

(4)

(5)

Error, (in dsolve) found differentiated functions with same name but depending on different arguments in the given DE system: {T(L), T(x)}

Download ExactSol.mw

improve integration speed...

Asked: mehdi jafari 749 Product: Maple

November 18 2022

1 0

hi. i want to improve my integration calculation speed, it takes me hours to calculate the results for even N=8. but i want for much more N's such as 20 30. can calculation speed improve? thanks in advance

Download M.mw

Error, (in Optimization:-NLPSolve) could...

Asked: mehdi jafari 749 Product: Maple 2021

October 14 2022

1 6

i have a problem in an optimzation problem. in the problem using NLPSolve to find the minimum, i have an integration which i use the Int command to be solved in the optimization process, but this error occures: Error, (in Optimization:-NLPSolve) could not store Int(..) in a floating-point rtable
please help to solve the problem, tnx in advance

>	restart:with(LinearAlgebra):

N:=3:

>	m:=Vector([ 1 , log(x+b3) , b2/(x+b3) ]):

A:=m.m^+:

>	for i to N do m\|\|i:=eval(A,[x=x\|\|i]); od:

>	M:=add(w\|\|im\|\|i,i=1..N-1)+(1-add(w\|\|i,i=1..N-1))m\|\|N:

>	MM:=( LinearAlgebra:-Trace(MatrixInverse(M)) ):

>	IF1:=evalf(Int(MM,[b2=1..2,b3=1..2],method = _d01ajc,epsilon=0.001)):

>	s:= Optimization:-NLPSolve(IF1,w1=0..1,w2=0..1,x1=1..10,x2=1..10,x3=1..10,variables=[w1,w2,x1,x2,x3],initialpoint={w1=0.6,w2=.1,x1=8,x2=7,x3=5},maximize=false,method=modifiednewton)

Error, (in Optimization:-NLPSolve) could not store Int(Int(16.6666666666666679*(-448.000000000000057*ln(7.+b3)*ln(5.+b3)+76.1999999999999886*ln(8.+b3)^2*b3^2+.199999999999999956*ln(8.+b3)^2*b3^4+.399999999999999911*ln(5.+b3)^2*b3^4+527.500000000000000*ln(5.+b3)^2+780.799999999999727*ln(8.+b3)^2+191.100000000000023*ln(7.+b3)^2+89.0999999999999943*ln(5.+b3)^2*b3^2+9.79999999999999893*ln(5.+b3)^2*b3^3+6.39999999999999858*ln(8.+b3)^2*b3^3+400.*ln(8.+b3)^2*b3+12.3000000000000025*ln(7.+b3)^2*b3^2+84.0000000000000142*ln(7.+b3)^2*b3+356.*ln(5.+b3)^2*b3+.600000000000000089*ln(7.+b3)^2*b3^3-1176.*ln(8.+b3)*ln(5.+b3)+280.*ln(8.+b ... 99999999999716*ln(7.+b3)*ln(5.+b3))^2), b2 = 1. .. 2.), b3 = 1. .. 2.) in a floating-point rtable