function [t,y]=ode1(h,tspan,y0)
%differential equation solver framework using Euler method

tinitial=tspan(1);
tfinal=tspan(2);
tvec(1)=tinitial;
yvec(1)=y0;
for i=2:(tfinal/h+1)
    tvec(i)=tvec(i-1)+h;
    yvec(i)=yvec(i-1)+h*yvec(i-1);
    i=i+1;
end
t=tvec;
y=yvec;
end