It really should mention the closed form solution, it's quite silly to compute a linear regression this way. It should also give a nod to robustness, a pair of

It really should mention the closed form solution, it's quite silly to compute a linear regression this way. It should also give a nod to robustness, a pair of sufficiently crazy outliers would leave the line nowhere near the points, seemingly in contradiction that lines the "fit" better will have a lower error value. (They will, only in the circular sense where you've defined fit in terms of that particular error function)...