3-35 할리데이 10판 솔루션 일반물리학

$$\begin{cases} \vec p:(3.50,220^\circ)\\ \vec q:(6.30,75.0^\circ)\\ \end{cases} $$
(a)$\vec p \times \vec q=?$ $$ \begin{aligned} \Ans =& \vec p \times \vec q\\ =&pq\sin\phi\\ =&3.50\cdot6.30\sin(220^\circ-75.0^\circ)\\ \approx&12.7 \, ,-z \text{ Direction} \end{aligned} $$
(b)$\vec p \cdot \vec q=?$ $$ \begin{aligned} \Ans =& \vec p \cdot \vec q\\ =&pq\cos\phi\\ =&3.50\cdot6.30\cos(220^\circ-75.0^\circ)\\ \approx&-18.1 \end{aligned} $$