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Step-by-step explanation:
The angle between vectors is given by
[tex]\cos{\theta} = \dfrac{\vec{\textbf{a}}\cdot \vec{\textbf{b}}}{|\vec{\textbf{a}}||\vec{\textbf{b}}|}[/tex]
The magnitudes for the vectors are as follows:
[tex]|\vec{\textbf{a}}| = \sqrt{a_x^2 + a_y^2 + a_z^2}[/tex]
[tex]\:\:\:\:\:\:\:=\sqrt{(2)^2 +(-5)^2 + (3)^2} = 6.16[/tex]
[tex]|\vec{\textbf{b}}| = \sqrt{b_x^2 + b_y^2 + b_z^2}[/tex]
[tex]\:\:\:\:\:\:\:= \sqrt{(3)^2 + (1)^2 + (4)^2} = 5.10[/tex]
The dot product between the vectors is
[tex]\vec{\textbf{a}}\cdot \vec{\textbf{b}} = (2)(3) + (-5)(1) + (3)(4) = 13[/tex]
Therefore, the angle between the two vectors is
[tex]\cos{\theta} = \dfrac{\vec{\textbf{a}}\cdot \vec{\textbf{b}}}{|\vec{\textbf{a}}||\vec{\textbf{b}}|} = \dfrac{13}{(6.16)(5.10)}[/tex]
or
[tex]\theta = 65.56°[/tex]