http://betterexplained.com/articles/intuitive-trigonometry/ http://betterexplained.com/articles/intuitive-trigonometry/ and the whole Better Explained website i

http://betterexplained.com/articles/intuitive-trigonometry/ http://betterexplained.com/articles/intuitive-trigonometry/ and the whole Better Explained website is pretty great for things like this. Their article on the constant e is what finally helped me to understand what e was: http://betterexplained.com/articles/an-intuitive-guide-to-exponential-functions-e/ http://betterexplained.com/articles/an-intuitive-guide-to-ex...