Element-wise matrix operations are multithreaded by default in your MATLAB version. In fact, this has been true since R2008a.
For your problem, it seems like X.*X is too small of a computation to see the multithreaded effect. From your System Monitor image, the whole computation took about 20 seconds, which means that each loop (X.*X) is taking only about 0.2 seconds, so that's not long enough to see the effect. Note that for-loops are not multithreaded. To see the effect, you need to be looking at a long (single) computation. Try something like
X=ones(10000);
sqrt(X).^sqrt(X).^sqrt(X).^sqrt(X).^sqrt(X).^sqrt(X)
or something like that.
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