Trigonometry
Advanced

Half Angle: Sine

Sine of half an angle.

Formula

sin⁡θ2=±1−cos⁡θ2\sin\frac{\theta}{2} = \pm\sqrt{\frac{1-\cos\theta}{2}}

Variables

\thetaAngle

Did You Know?

Half-angle formulas let surveyors bisect angles precisely using only addition and square roots.

half angleidentity