Question

I NEED HELP PLEASE, THANKS! :)

Answer 1

Answer:

Step-by-step explanation:

Cos θ = u*v    

             IuI *IvI

u * v = 7*(-1) + (-2)*2

       = -7 - 4

      = -11

IuI = $\sqrt{7^{2}+(-2)^{2}}$

    = $\sqrt{49+4}$

    = $\sqrt{53}$

I vI = $\sqrt{(-1)^{2}+2^{2}}$

     = $\sqrt{1+4}$

      = $\sqrt{5}$

Cos θ = $\frac{-11}{\sqrt{53}*\sqrt{5} }$

          = $\frac{-11}{16.28}$

   Cos θ = -0.68

θ = 132.5°