# High School Trigonometry/Half-Angle Identities

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**Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "/mathoid/local/v1/":): {\displaystyle \tan^{2}{u} = \frac{1 - \cos{2u}}{1 + \cos{2u}}}**

This material was adapted from the original CK-12 book that can be found here. This work is licensed under the Creative Commons Attribution-Share Alike 3.0 United States License