Using ()

It is possible to speed things up, using parentheses, to change the order of evaluation. Test the following code segment and explain your results:

n = 1000;
v = randn(n, 1);
a = randn(n, 1);
loops = 100;

tic
  for j = 1:loops
    A = v * v';
    y = A * a;
  end
toc

tic
  for j = 1:loops
    y = v * v' * a;
  end
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tic
  for j = 1:loops
    y = v * (v' * a);
  end
toc