Index exceeds the number of array elements (1). Error in heun_method (line 15) K1(i)=fprime(x(i),y(i));

function heun_method(fprime,y0,dx,x0,b,n)
clear variables;
clc;
x0 = 0;
y0 = 1;
n = 10;
b = 1;
fprime = inline('2-3*X+4*Y', 'X', 'Y')
dx = (b-x0)/n;
x(1)=x0;
y(1)=y0;
i=1;

for i=1:n
K1(i)=fprime(x(i),y(i));
K2(i)=fprime(x(i)+dx,y(i)+K1(i)*dx);
y(i+1)=y(i)+.5*dx*(K1(i)+K2(i))

end
x,y
 
plot(x,y,'r')
xlabel('x')
ylabel('y')
 end 

Answer 1

[JESUS DAVID ARIZA ROYETH]

function heun_method(fprime,y0,dx,x0,b,n)
clear variables;
clc;
x0 = 0;
y0 = 1;
n = 10;
b = 1;
fprime = inline('2-3*X+4*Y', 'X', 'Y')
dx = (b-x0)/n;
x(1)=x0;
y(1)=y0;
i=1;
for i=1:n
K1(i)=fprime(x(i),y(i));
K2(i)=fprime(x(i)+dx,y(i)+K1(i)*dx);
y(i+1)=y(i)+.5*dx*(K1(i)+K2(i))
x(i+1)=x+dx;
end
x,y
 
plot(x,y,'r')
xlabel('x')
ylabel('y')
 end