Unit 4, Day 7

Agenda

1. Number talk: Always, Sometimes, Never — $|\vec{a}\times \vec{b}|\le |\vec{a}||\vec{b}|$
2. Random groups: wanted — one arrow perpendicular to two given arrows at once; build it from equations, not from luck
3. Consolidate: The Cross Product — a product that points, and the area it happens to measure along the way
4. Practise: Dot and Cross Product Practice — the rest

Things to do before our next class

• Journal: the dot product returns a number, the cross product a vector. Why does each job need its own kind of answer?