vault backup: 2024-12-02 10:18:13

education/math/MATH1060 (trig)/Vectors.md

@@ -40,3 +40,8 @@ The dot product of two vectors $\vec{u} = \langle a, b \rangle$ and $\vec{v} = \
 
 - Given that $\vec{u} = \langle -7, 3 \rangle$, and $\vec{v} = \langle -3, 4 \rangle$, find $\vec{u} * \vec{v}$.
 - $\vec{u} * \vec{v} = -7 * -4 + 3 * 4$
+
+The dot product can be used to find the angle between two vectors.
+
+If $\theta (0\degree < \theta < 180\degree)$, is the angle between two nonzero vectors $\vec{u}$ and $\vec{v}$, then
+$$ \cos\theta = \dfrac{\vec{u}*\vec{v}}{|\vec{u}||\vec{v}|} $$