Items tagged with integration integration Tagged Items Feed

Good Morning,

This is the script that I have used to to an integration, as the command ''int'' didn't work because the coputation was really heavy.


p_old := 0;

g := 0; #index

E_tot_net_Point := 0;

for g to 2 do

 h := g+1;

 loopstart := SP_time[g];

 loopend := SP_time[h];

  for tt from loopstart by 0.01 to loopend do

   t := tt;

   P_tot_net_Fkt := t -> C_motore[g]*omega_motore[g]

if t≠SP_time[g] and t ≠ SP_time[h] then

 P_tot_net_Point := P_tot_net_Fkt(t);

 P_tot_net_Point_next := P_tot_net_Fkt(t+0.001);

 plt_P_tot_net_plt[t] := pointplot([t, P_tot_net_Point]);

 E_tot_net_Point := E_tot_net_Point+(P_tot_net_Point*0.01);

 plt_E_tot_net_plt[t] := pointplot([t, E_tot_net_Point]);

 p_old := P_tot_net_Point;

end if;      

  end do:

end do:

plots:-display(entries(plt_E_tot_net_plt, 'nolist'), title = "Energy", color = "Red", symbol = point, symbolsize = 20, gridlines = true, size = [1000, 500], labels = ['[s]', '[Watt*s]'], font = [axes, 12])


I have plotted the function as a series of points over the orizontal axis (t).

 

Now I would like to calculate the last value of the curve (which is itself a point) as a function of the orizontal axes t. How can I do it?

Something like E_tot_net_Point = f(t)

 

Thank you for the help

Hello everyone !

I have a problem when I want to calculate the following multiple integration numerically:

>evalf(Int(exp(sum(x[i],i=1..6)^2),[seq(x[i]=-1..1,i=1..6)]));
  value(%);

It doesn't work. But when I replace sum(x[i],i=1..6)^2 with sum(x[i],i=1..6), it works. Is there any feasible solution to my problem ?

Thank you for reading !

 

I think Simpson's rule for integration is very simple and it is just function evaluation over a few points on the interval of integration. So we expect it to be fast.

When I use it as a summation command (using Simpson's formula) it is really fast but when I use the command ApproximateInt with Simpson method it is sometimes really slow. For example

restart;

f := unapply(x^2/(sin(x)+x+1), x);

with(Student[Calculus1]);

evalf(ApproximateInt(f(x), x = 1 .. 2, method = simpson, partition = 20));

or even with partition=10 you must wait for a long time.

Please help.

Thank you

HI,

 

wondered if anyone knows how to make proper use of the large operators pallete on the list of pallettes on the left. For example when using the contour integration symbol on the left how do you enter the delimiters. 

I always get the error: "Error, unable to match delimiters". The help on this is not useful for this case. 

 

Thanks. 

 

It seem absurd that in Maple 18, why int(f(t),t) do not work instead one have to write Int(f(t),t) for indefinite integration?

 

How to compute integral of complicated function in maple 

int(e^(-s)*ln(1+s*e^-s)ds)from 0 to t 

i can not computed and how to simplify the integral because the wieght of calculation is to big?


I have a problem about the integration of a function. The maple returns mathematical form of the given command

the function is

fn :=(-4.079067798*10^(-16)+3.422708023*10^(-16)*I)*(3.363377947*10^(-11)+5.977507284*10^(-12038)*I+(3.363377947*10^(-11)+4.678081798*10^(-22)*I)*erf(1.664331698*10^15*qq-0.2503507367e-1-4.649313602*I)) *exp(-2.77*(qq/(tau*tau))^2)*exp(-I*w0*qq)*exp(-(ss-qq)/T_pop)

qq is the integration variable qq=-inf..ss

w0=10^15

tau=10^(-15)

T_pop=30e-15

Dear friends,

 

I am trying to do an integration which consists of a list of data; let me explain it more:

I have to do

however, I do not have f(x) in the form of a function. f(x) is a list which is:

also, I have x as

How can I do the integration between 1<x<6 ?

 

 

 

 

I am trying to integrate solutions to a set of differential equations I have obtained numerically but keep getting this error:

Error, (in solW) invalid input: subs received sol(r), which is not valid for its 1st argument

For simplicity, let's say I am interested in integrating the function W(r), which I obtain from 

sol := dsolve({eqns, ics}, numeric, abserr = 10^(-10), relerr = 10^(-10), range = ymin .. ymax)

I then use

solW := r -> subs(sol(r), W(y))

This gives me W(r) for any r in the range ymin to ymax. But I cannot do anything with this function. For example, 

int(solW(r),r=ymin..ymax) or plot(solW(r),r=ymin..ymax) give the error above. I know that I can plot the solutions using odeplot, but is there something analogous for integrating the solutions? 

Thanks!

Completely new to maple. Not even sure where to start with this. Can't get the Simpson's or Trapezoidal Rule to work for me. Any help would be much appreciated

This is my first attempt at trying the units feature within Maple. I have had mixed results. I have a function defined that gives me values in [cal/mol/K], which is correct. But when I try to use this as the integrand in an integral definition it does not want to solve. I cannot determine what the problem is.

I thought that I possibly needed to define units in the integral expression, but this just produces more errors or locks-up Maple completely. (Side note: When Maple locks-up, the "interupt current operation" toolbar often does not correctly kill the operation, and I am forced to restart Maple :/)

As I have the problem defined, I should get the following result:

T__sys= 64.47487 [K], should get me HIG(T__sys) = -19682.7 [cal/mol].

See attached: EnthalpyTrace_-_Integrating_with_Units_Error.mw

Any help or insights would be greatly appreciated.

 

I have an arrays of data. One for x values, and one for y values. How can I obtain a numerical integration of y for a range of x values?

I have tried defining a function of X using ArrayInterpolation(x,y,X) and then calling evalf(Int(f,xmin..xmax)) but that gives an error message. (I don't seem to be able to paste into this window) The error message says

"Error, invalid input: evalf expects its 2nd argument, n, to be of type posint, but received numeric."

I thought I was using a form of the equation right from the help system.

I also tried the 2D version of integration, but it returns the difference of my limits times my function name.

I aslo tried AdaptiveQuadrature, but I can't get that to work either.

-Mike McDermott

Newbie Maple user

 

 

Just trying Maple again after 10+ years, so please bear with me. I am basically trying to do a symbolic integration, where the output should be the antiderivative of the function I am integrating. However, I have not been able to succesfully get the output I expect.

I defined a function Cp(T), with constants C1, C2, etc. like so:

C__p := T -> C__1+C__2(C__3/(T*sinh(C__3/T)))^2+C__4(C__5/(T*cosh(C__5/T)))^2 

But when I integrate the function using int(Cp(T), T=Tref..Tsys) it does not output the antiderivative as I would expect. This is what I am looking for, but it just gives me the equation within the integral sign without symbolically solving integral. Can this be done?

It should be,

int(Cp(T), T=Tref..Tsys) = C1*(T2-T1) + C2*C3[coth(C3/T2) - coth(C3/T1)] - C4*C5[tanh(C5/T2)-tanh(C5/T1)]

Trivial integrals such as int(x2,x) = 2x solve okay, so I am assuming I setup the problem incorrectly. I just cannot figure out what I did wrong, and it is driving me crazy. I already wasted more time than is healthy on this. Any help would be greatly appreciated. Thanks.

Please help me to solve this integration

restart; with(LinearAlgebra); int(exp(-(ln(z/(snr*B^2))+4*sigma^2)^2/(32*sigma^2))*eta^2*(y/z)^((1/2)*eta^2-1)/(z*sqrt(32*Pi*sigma^2)*(2*sqrt(y*z))*(2*A[o]^(eta^2))), z, z = y/A[o]^2 .. infinity);

 

 

 

restart; with(LinearAlgebra); int(exp(-(ln(z/(snr*B^2))+4*sigma^2)^2/(32*sigma^2))*eta^2*(y/z)^((1/2)*eta^2-1)/(z*sqrt(32*Pi*sigma^2)*(2*sqrt(y*z))*(2*A[o]^(eta^2))), z, z = y/A[o]^2 .. infinity)

Trying a few integrals in Maple -- doesn't seem to handle them very well. Any workarounds please?

 

f1(p,b):= 1/(p^2 + b^2)^2 ;

f2(p,b):= exp(-p/b)^2;

T1pbm := Int(q*f1(q, b)*ln((p+q)^2+m^2), q = 0 .. infinity);

T2pbm := Int(q*f1(q, b)*ln((p-q)^2+m^2), q = 0 .. infinity);

with(IntegrationTools):

PT1 := evalf(Parts(T1pbm, q*f1(q, b), ln((p+q)^2+m^2)));

PT2 := evalf(Parts(T2pbm, q*f1(q, b), ln((p-q)^2+m^2)));

Ev := evalf(-pi*c*Int*(p*f1(p, b)*(PT1-PT2), p = 0 .. infinity))

1 2 3 4 5 6 7 Last Page 1 of 11