function E=euler(f,a,b,ya,M)

%Input   - f is the function entered as a string 'f'
%        - a and b are the left and right endpoints
%        - ya is the initial condition y(a)
%        - M is the number of steps
%Output  - E=[T' Y'] contains the values for the approximate solution



h=(b-a)/M;
T=zeros(1,M+1);
Y=zeros(1,M+1);
T=a:h:b;
Y(1)=ya;

for j=1:M
   Y(j+1)=Y(j)+h*feval(f,T(j),Y(j));
end

E=[T' Y'];