# Scalar Product of Vectors

$\stackrel{\to }{a}·\stackrel{\to }{b}=|\stackrel{\to }{a}||\stackrel{\to }{b}|cos\alpha$
$\stackrel{\to }{a}·\stackrel{\to }{b}={x}_{1}·{x}_{2}+{y}_{1}·{y}_{2}$

## In case of 3D:

$\stackrel{\to }{a}={x}_{1}\stackrel{\to }{i}+{y}_{1}\stackrel{\to }{j}+{z}_{1}\stackrel{\to }{k}$
$\stackrel{\to }{b}={x}_{2}\stackrel{\to }{i}+{y}_{2}\stackrel{\to }{j}+{z}_{2}\stackrel{\to }{k}$
$\stackrel{\to }{a}·\stackrel{\to }{b}={x}_{1}·{x}_{2}+{y}_{1}·{y}_{2}+{z}_{1}·{z}_{2}$
Keywords: multiplication of vector, scalar multiplication, scalar product of vectors