Re: ind the angle between the given vectors to the nearest tenth of a degree u = <2, -4>, v = <3, -8>

To find this, we can use this

arcos [(u dot v) / (llull * llvll] = θ

 

Let's find the dot product of u and v    We have

(2*3) + ((-4) * ((-8)) = (6 + 32) = 38

Now, let's find the length of u = llull = SQRT[2^2 + (-4)^2] = SQRT(4 + 16) = SQRT(20) = 2*SQRT(5)

And let's find the length of v = llvll = SQRT[3^2 + (-8)^2] = SQRT(9 + 64) = SQRT(73)

So putting this all together, we have

arcos [38 / (2*SQRT(5) * SQRT(73)] = arcos [19 / SQRT(365)] ≈ 6º