Exercise 1.2.26

Answers

These two lines add to $2 ∥ v ∥^{2} + 2 ∥ w ∥^{2} :$

\begin{aligned} ∥ v + w ∥^{2} = (v + w) \cdot (v + w) = v \cdot v + v \cdot w + w \cdot v + w \cdot w \\ ∥ v - w ∥^{2} = (v - w) \cdot (v - w) = v \cdot v - v \cdot w - w \cdot v + w \cdot w \end{aligned}

mathchakra

2021-11-20 14:09