f ( θ ) = sin ( θ ) {\displaystyle f(\theta )=\sin(\theta )} g ( θ ) = cos θ {\displaystyle g(\theta )=\cos {\theta }} θ = 60 ∘ {\displaystyle \theta =60^{\circ }} then g ( θ 2 ) {\displaystyle {\text{then }}g\left({\frac {\theta }{2}}\right)}
