## Calculus (3rd Edition)

$(0, \pi/5,1/2) \Longrightarrow (0, 0,1/2)$.
We have $$r=0, \quad \theta =\pi/5, \quad z=1/2.$$ Now, we have $$x=r\cos \theta=0,$$ $$y=r\sin \theta=0,$$ $$z=1/2.$$ So, $(0, \pi/5,1/2) \Longrightarrow (0, 0,1/2)$.