Use the law of cosines to find the value of cos(theta). Round your answer to two decimal places.

Please explain. Thank you!

Question

Use the law of cosines to find the value of cos(theta). Round your answer to two decimal places.

Please explain. Thank you!

kj4uts · Answer

attachment

kainui · Answer

First off, what's the law of cosines say? $$\Large \bar a \cdot \bar b = |\bar a||\bar b| \cos \theta$$ It says the dot product of two vectors is equal to their lengths multiplied together times the cosine of the angle between them.

You just want cos theta though, so you will have to just divide both sides of the equation by those lengths to isolate cosine by itself. Then you will have the formula you need!

kj4uts · Answer

attachment

kj4uts · Answer

@Kainui The work I did is above I got B. 0.21 as my answer I am not sure if that is right. Would you mind checking that for me?

kainui · Answer

I'm sorry I have to leave right now.

kj4uts · Answer

Oh ok thanks for your time though.

anonymous · Answer

what was it?

kj4uts · Answer

@PierceTheCrys1115 it was B. 0.21