Question

Find the angle between the given vectors to the nearest tenth of a degree.

u = <2, -4>, v = <3, -8>

Answer 1

okay I understand that the formula is \[\cos \theta = u \times v \div \left| u \right|\left| v \right| \]
I plug in everything and then finally get \[38\div \sqrt{13}\sqrt{80}\]
Now I have no idea what to do after this...

Answer 2

@jazzie Read throuh this http://tutorial.math.lamar.edu/Classes/CalcII/DotProduct.aspx

Answer 3

u.v=38
|u||v|=sqrt(20*73)
angle=arccos(38/sqrt(1460))

6°

Answer 4

Okay I understand now. Thank you !!