I ijd5000 Junior Member Joined Sep 3, 2013 Messages 51 Sep 12, 2013 #1 The question asks to simplify cos(2 arctan (x)) the '2' is whats throwing me off, i know it would be 1/sqrt(1+x^2) if it wasn't there.
The question asks to simplify cos(2 arctan (x)) the '2' is whats throwing me off, i know it would be 1/sqrt(1+x^2) if it wasn't there.
D daon2 Full Member Joined Aug 17, 2011 Messages 999 Sep 12, 2013 #2 \(\displaystyle \cos(2\cdot(\ddot\smile)) = \cos^2(\ddot\smile) - \sin^2(\ddot\smile)\) The set up the triangle for \(\displaystyle \tan(\ddot\smile) = \dfrac{x}{1}\) and find the cosine and sine of it.
\(\displaystyle \cos(2\cdot(\ddot\smile)) = \cos^2(\ddot\smile) - \sin^2(\ddot\smile)\) The set up the triangle for \(\displaystyle \tan(\ddot\smile) = \dfrac{x}{1}\) and find the cosine and sine of it.
