f ( θ ) = sin ( θ ) {\displaystyle f(\theta )=\sin(\theta )}
θ = 60 ∘ {\displaystyle \theta =60^{\circ }}
f ( 2 θ ) {\displaystyle f(2\theta )}
f ( 2 θ ) = f ( 2 ⋅ 60 ∘ ) = f ( 120 ∘ ) = sin ( 120 ∘ ) = 3 2 {\displaystyle f(2\theta )=f(2\cdot 60^{\circ })=f(120^{\circ })=\sin(120^{\circ })={\frac {\sqrt {3}}{2}}}
