Solving ODEs using Runge Kutta Methods

Total of 5 curves

So I'm to solve the above problem using 4 different methods and then display all 5 curves in the same graph. But it appears something is not right and I can't figure it out. I have attached my code to this message. After I ran the code, I got an error which I have been trying to fix, particularly the inline feature and I dont even know why the ode45 is also giving an error.

My code and the error below it

f=inline('y*t^2-1.5*y','t','y');
t0=0;
y0=1;
tf=2;
tspan = [t0 tf];
[t,y]=ode45(f,tspan,y0);
hold on
plot (t,y,'r')

clear t
h=0.5;
t(1)=t0;
euler5(1)=y0;
for i=1:4
t(i+1)=t(i)+h;
euler5(i+1)=euler5(i)+h*f(t(i),euler5(i));
end;
plot(t,euler5,'g')

clear t
h=0.25;
t(1)=t0;
euler25(1)=y0;
for i=1:8
t(i+1)=t(i)+h;
euler25(i+1)=euler25(i)+h*f(t(i),euler25(i));
end;
plot(t,euler25,'b')

clear t
h = 0.5;
midpoint(1) = y0;
t(1) = t0;
for i = 1 : 4
t(i+1) = t(i) + h;
z = midpoint(i) + h/2* f(t(i),midpoint(i));
midpoint(i+1) =midpoint(i) + h * f(t(i)+h/2,z);
end;
plot(t,midpoint,'y')

% Displays title information
h=0.5 ;
ta(1)=t0 ;
ya(1)=y0 ;

for i=1:4
% Adding Step Size
ta(i+1)=ta(i)+h ;

% Calculating k1, k2, k3, and k4
k1 = f(ta(i),ya(i)) ;
k2 = f(ta(i)+0.5*h,ya(i)+0.5*k1*h) ;
k3 = f(ta(i)+0.5*h,ya(i)+0.5*k2*h) ;
k4 = f(ta(i)+h,ya(i)+k3*h) ;

% Using 4th Order Runge-Kutta formula
ya(i+1)=ya(i)+1/6*(k1+2*k2+2*k3+k4)*h ;
end

plot(t,ya,'c')
legend('Exact','Eluer ,width 0.5','Euler width 0.25','Midpoint','RK fourth Order')

THIS IS THE Error I got.

Your knowledge and corrections are highly appreciated.

Answer 1

[Torsten]

f = @(t,y)y(1)*t^2-1.5*y(1)

instead of

f=inline('y*t^2-1.5*y','t','y');

Answer 2

[Meysam Mahooti]

https://www.mathworks.com/matlabcentral/fileexchange/55430-runge-kutta-4th-order?s_tid=srchtitle

https://www.mathworks.com/matlabcentral/fileexchange/61130-runge-kutta-fehlberg-rkf78?s_tid=srchtitle