format long e
a=0;
b=1;
n=65;
h=(b-a)/n;
g=@(x) a+h*x;
f=@(x) exp(-x);
s=0;

for j=1:n-1
  s=s+f(g(j));
end

t=h/2*(f(0)+2*s+f(1));
t