x = zeros(50,1);
y1 = zeros(50,1);
y2 = zeros(50,1);

fprintf('\n\ncomputing f(x) version 1\n\n');
for k = 1:50,
  x(k) = 2^(-k);
  y1(k) = exp1(x(k));
  fprintf('k = %3d, x = %23.15e, ', k, x(k));
  fprintf('f(x) = %23.15e \n', y1(k));
end 

fprintf('\n\n\n\n');
fprintf('computing f(x) version 2\n\n');
for k = 1:50,
  y2(k) = exp3(x(k));
  fprintf('k = %3d, x = %23.15e, ', k, x(k));
  fprintf('f(x) = %23.15e \n', y2(k));
end 

k = [1:50]';
figure(1); hold off;
plot(k,log2(abs(y1-1)),'r','Linewidth',2); hold on;
plot(k,log2(abs(y2-1)),'bx','Linewidth',2)