March 2023

Law of cosines

Submitted by perfectveneer777 on March 6, 2023 - 1:49pm

I saw on a website, law of sines are transposed. Example:
c^2=a^2+b^2-2abcos(C)
Transposed: cos(C)= a^2+b^2-c^2/2ab
I need a proof how it became this way.