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Discussion of Problem 1075. Thread in a Space

Help me with trigonometry.
Posted by Yegor Suvorov 26 May 2007 16:53
I know cos(a) (Ac) and cos(b) (Bc). I need to get cos(b - a). How can I do it? I do it like this: cos(arccos(Bc) - arccos(Ac)). Maybe I can do it easier?
cos(a-b)= cos(a)cos(b)+sin(a)sin(b) (-)
Posted by diver_ru 26 May 2007 23:47