Hw5 ex1 - norm minimization

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, $||{\dot {x}}||$ is generally already defined as ${\sqrt {{\dot {x}}^{T}{\dot {x}}}}$.

--Elisa