- #1
Deathcrush
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Homework Statement
Well, I'm having problems with this script, I'm taking my first course on differential equations, and I am trying to write a script that approximates the values of the solution of a differential equation, and compares them to the exact solution using a table of values, it must also calculate the error, the problem is that I cannot make the table to appear using a column for each variable, instead, the values are spread horizontally and everything is pretty messed up, Its the first time I use Matlab and I might have a lot more mistakes, can anyone help me?
Homework Equations
the equations are pretty simple, they are in the bottom of the script I wrote
The Attempt at a Solution
this is what I wrote
function [t P] = Euler(t0,P0,L,N) % Nombrando la función y estableciendo los datos necesarios
Close all;
h=L./N; % estableciendo tamaño de paso
t=[]; P=[]; % t y P son vectores vacíos
t(1)=t0+h;
P(1)=P0+h.*f(t0, P0); % Estableciendo los primeros componentes de t y P
for n=1:N-1
t(n+1)=t(n)+h;
P(n+1)=P(n)+(h.*(f(t(n), P(n))));
end
Paprox=P;
Pexacta= SolucionExacta(t);
error=abs(Pexacta-Paprox);
% Para imprimir la tabla
fprintf(' t Paproximada Pexacta error \n');
fprintf('---------------------------------------------------------------------------------\n');
fprintf( '%10.5f %10.5f %10.5f %10.5f', t ,Paprox, Pexacta, error);
% Para graficar
plot(t,P);
hold on
plot(t,Pexacta);
figure;
plot(t, error);
end
function ret=f(t,P)%para insertar la ecuación diferencial que deseamos resolver por aproximación
ret=(0.0225.*P-(0.0003.*(P.^2)));
end
function f=SolucionExacta(t) % Para establecer la solución aproximada y hacer comparación
f=(0.5625.*exp(0.0225.*t))./(0.015+(0.0075.*exp(0.0225.*t)));
end