2 Intuitive ways to prove.
With the growth of generative AI and chatGPT. I discussed some questions about machine learning with a DS friend. when we talked about vectors and similarity, then we talked about dot products. so my fundamental math question is:
why is the dot product of 2 vectors which means the length of 2 vectors * cos(the angle between them) = (x1*y1+x2*y2)?
He explained in 2 ways, both easy to understand. (only need high school math)
#1 Cosine law
#2 Start from definition
That’s it. thanks for reading.