Question

PLEASE HELP ME!!!!!!!! 

Answer 1

Angle θ between two vectors is given by, $\theta =cos^{-1}( \frac{u \cdot v}{|u||v|} )$; where $u \cdot v=-5(-4)+(-4)(-3)=20+12=32$; $|u|= \sqrt{ (-5)^{2} + (-4)^{2} } = \sqrt{25+16} = \sqrt{41}$ and $|v|=\sqrt{ (-4)^{2} + (-3)^{2} } = \sqrt{16+9} = \sqrt{25}=5$.
Therefore, $\theta =cos^{-1}( \frac{32}{ 5\sqrt{41}} )=cos^{-1}0.9995=1.8^o$