Numerically solving an integral with multiple variables.

3 次查看（过去 30 天）
Ausamah Hobbi
Ausamah Hobbi 2018-11-28
评论： Ausamah Hobbi 2018-11-28
Hello. I am in dire need of help. I'm trying to numerically solve this integral, the Formula is on the third page (of the attached pdf) -- the F(1/2). I've tried different function handles but am coming up with nothing. Here are some things that I tried. I want Vg and Vd to be varying with this. Don't give me the whole answer but where can I even start? How do I start? I'm just unsure how to integrate at this point.
% INITIALIZE MATLAB
close all;
clc;
clear all;
syms x
syms Ro
syms Vd
syms Vg
syms CoRo %Constant of p
syms p
Vt = 0.7;
Vg = 2;
CoRo = 1.652e+16;
%Vg = 0:0.2:1.2;
% Ro
p = CoRo*(Vg-Vt);
% FUNCTIONS AND INTERVAL
a = @(Vd) 1+exp(Vd);
b = @(Vd)sqrt(a^2+4*exp(Vd)*(exp(p)-1));
u = @(Vd) log(b-(1+exp(Vd))-log(2));
f = @(u) sqrt(u)/(1+exp(u-x));
%a = inline(1+exp(Vd));
%b = inline('sqrt(a^2+4*exp(Vd)*(exp(p)-1))','Vd');
%u = inline('log(b-(1+exp(Vd))-log(2))','Vd');
%f = inline('sqrt(u)/(1+exp(u-x))','u');
d = integral(f,0,5)
% INTEGRAL
%Starting value
%s = 0;
%Ending value
%e = 5;
%F = integral(f,s,e);
% NUMBER OF POINTS
N = 10;
% INTEGRAL OF f

请先登录，再回答此问题。

回答（1 个）

Torsten
Torsten 2018-11-28
编辑：Torsten 2018-11-28
f = @(u,x)sqrt(u)./(1+exp(u-x));
F = @(x)integral(@(u)f(u,x),0,Inf,'ArrayValued',true);
F([2 4])
  1 个评论
Ausamah Hobbi
Ausamah Hobbi 2018-11-28
Thank you! It works. Now just some questions for my own reference, if you don't mind.
  • What does 'ArrayValued' do?
  • What does F([2 4]) do? Is it just values for x at 2 and 4?
  • What does the '.' do in the first line?
My next part of this is to vary the value of Vg. Does what I have "Vg = 0:0.2:1.2;" work? As well as varying Vd for which I have an excel file for. Any suggestions there?
Thank you very much!

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Programming 的更多信息

标签

产品


版本

R2018b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by