diff --git a/docs/mcv4u7.md b/docs/mcv4u7.md index 36f6a6b..c2745e0 100644 --- a/docs/mcv4u7.md +++ b/docs/mcv4u7.md @@ -378,6 +378,24 @@ The sum of two vectors can also be solved diagrammatically by envisioning the he (Source: Kognity) +### Dot product + +Also known as the scalar product, the dot product between two vectors returns a **scalar** value representing the horizontal displacement after multiplication. Wheree $\theta$ is the angle contained between the vectors $\vec{u}$ and $\vec{v}$ when arranged tail-to-tail: +$$\vec{u}\bullet\vec{v}=|\vec{u}||\vec{v}|\cos\theta$$ + +!!! note + This implies that vectors perpendicular to one another must have a dot product of zero. + +Much like regular multiplication, dot products are: + + - communtative — $\vec{u}\bullet\vec{v}=\vec{v}\bullet\vec{u}$ + - distributive over vectors — $\vec{u}\bullet(\vec{v}+\vec{w})=\vec{u}\bullet\vec{v}+\vec{u}\bullet\vec{w}$ + - associative over scalars — $(m\vec{u})\bullet(n\vec{v})=mn(\vec{u}\bullet\vec{v})$ + - $m(\vec{u}\bullet\vec{v})=(mu)\bullet\vec{v}=(mv)\bullet\vec{u}$ + +When working with algebraic vectors, their dot products are equal to the products of their components. +$$\vec{u}\bullet\vec{v}=u_xv_x+u_yv_y$$ + ## Resources - [IB Math Analysis and Approaches Syllabus](/resources/g11/ib-math-syllabus.pdf)