# Hw5 ex1 - norm minimization

From Murray Wiki

Jump to navigationJump to search**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