Finding inverse tangent from sine?

Question

Im watching a video that goes from

$ p*sin(\phi - \theta) = 0 $

to

$ \phi - \theta = atan2(0,\pm1)$

without any intermediate steps. Could anyone explain the maths behind this? Unsure if its some trigonometric rule I'm missing.

Thanks!

Please note atan2 is the matlab inverse tangent function.

Answer 1

If $ \phi - \theta = x, p*\sin x = 0 $

then please note

$$ x = atan2(0,\pm 1 )$$

means angle $x$ radius vector tip is placed at $x=\pm 1$

$$ x= 0,\pi, 2 \pi,3 \pi ....$$