#$444.$ Vector Angle

For vectors $A=($:$-4,-2,1$:$)$ and $B=($:$5,0,-5$:$),$ what is the cosine of the angle between A and $B?$

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$A=[-4\mathrm{.}0,-2\mathrm{.}0,1\mathrm{.}0]$;$\%$

$B=[5\mathrm{.}0,0\mathrm{.}0,-5\mathrm{.}0]$;$\%$

Cosine of Angle $=$ number rtol$=0\mathrm{.}01,$ atol$=1$e$-$