Half-angle formulas

Half angle identities:

• $\sin {\left({\frac {x}{2}}\right)}=\pm {\sqrt {\frac {1-\cos {x}}{2}}}$

• $\cos {\left({\frac {x}{2}}\right)}=\pm {\sqrt {\frac {1+\cos {x}}{2}}}$

• $\tan {\left({\frac {x}{2}}\right)}=\pm {\sqrt {\frac {1-\cos {x}}{1+\cos {x}}}}$

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 "https://wikimedia.org/api/rest_v1/":): {\displaystyle = \frac{\sin{x}}{1 + \cos{x}} }

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 "https://wikimedia.org/api/rest_v1/":): {\displaystyle = \frac{1 - \cos{x}}{\sin{x}} }

Resources

• Half-angle formulas. Written notes created by Professor Esparza, UTSA.