Hw5 ex1 - norm minimization

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Q How do we solve the minimization problem for {\sqrt  {||{\dot  {x}}||}}?

A The minimization of the square root of the norm is difficult, but it's doable by just taking the derivative of the {\sqrt  {\cdot }} function; though one will have the same result by minimizing just ||{\dot  {x}}||, where with this notation we mean {\dot  {x}}^{T}{\dot  {x}}.

Note that in the literature, ||x|| is generally already defined as {\sqrt  {x^{T}x}}.