When I run my code, I keep getting this error: "The following error occurred converting from sym to double: Unable to convert expression into double array."

clc;
clear;
close;
x=linspace(0,1,100);
solinit = bvpinit(x,[2 4]);
y = bvp4c(@ode2, @bc2, solinit);% ВЫЗЫВАЕМ СОЛВЕР BVP4C:
y=deval(y,x);
plot(x,y(1,:));
grid on
legend('y(t)');
xlabel('t');
function dy = ode2(~, y)%y''+y'=1+int^1_0(y'*x)dx;y(0) = 2;y(1) = 4;
dy=zeros(2,1); % создает нулевой вектор-столбец 
dy(1)=y(2);
syms y(x) x
dy(2)=1-y(2)+int(y(2)*x,'x',[0 1]);
end
function res = bc2(ya, yb)
res = [ya(1)-2
    yb(1)-4];
end

Error in IDTboundary2>ode2 (line 16)

dy(2)=1-y(2)+int(y(2)*x,'x',[0 1]);

Error in bvparguments (line 105)

testODE = ode(x1,y1,odeExtras{:});

Error in bvp4c (line 130)

bvparguments(solver_name,ode,bc,solinit,options,varargin);

Error in IDTboundary2 (line 6)

y = bvp4c(@ode2, @bc2, solinit);% ВЫЗЫВАЕМ СОЛВЕР BVP4C:

Answer 1

[Torsten]

So you have a constant source term

int^1_0(y'*x)dx

in all grid points - independent of the position x in the interval [0 1] ?

Then use

x = linspace(0,1,100);
solinit = bvpinit(x,[2 4]);
source = 0;
tol = 1e-3;
error = 1.0;
while error > tol
  sol = bvp4c(@(x,y)ode2(x,y,source),@bc2,solinit);% ВЫЗЫВАЕМ СОЛВЕР BVP4C:
  source_new = trapz(sol.x,sol.x.*sol.y(2,:));
  error = abs(source_new - source);
  source = source_new;
end
plot(sol.x,sol.y(1,:));
grid on
legend('y(t)');
xlabel('t');

function dy = ode2(x,y,source)%y''+y'=1+int^1_0(y'*x)dx;y(0) = 2;y(1) = 4;
  dy = zeros(2,1); % создает нулевой вектор-столбец 
  dy(1)=y(2);
  dy(2)=1-y(2)+source;
end
function res = bc2(ya,yb)
  res = [ya(1)-2
         yb(1)-4];
end

[Nauryzbay]

Thank you So Much!

[Nauryzbay]

You helped me a lot. Thanks