I want to know where the cosine came from in the dot product.

Question

steve816 · Answer

A * B = |a||b| cos theta

steve816 · Answer

I am trying to understand this conceptually but I can't I don't get it!!!!

studygurl14 · Answer

The cos comes about because you are trying to find the angle given the two vectors. I'm a bit rusty on the topic, but this website explains it nicely http://tutorial.math.lamar.edu/Classes/CalcII/DotProduct.aspx

steve816 · Answer

I already went through that website, but I still am not understanding it for some reason.

jessikah · Answer

PLEASE SOMEONE HELP ME ON MY QUESTION I JUST POSTED PLEASE

irishboy123 · Answer

Maybe think about: Work = Force * Distance?

.... cos Physics & Engineering...... that's where so much of math comes from, like calculus and a load of other such stuff, and this idea.  

It is only that component of force acting in the direction travelled that does work.

$W = \vec F \bullet \vec x =  |\vec F || \vec x| \cos \theta$


Picture might be better at explaining this....

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