Question

Lay down the positions of the points whose polar coordinates are $(2a,-\frac{\pi }{2})$

Answer 1

$P(2a,-x/2)\equiv P(0,-2a)$

Given polar co-ordinates are $(2a,-\frac{\pi }{2})$
Then, $r=2a$ and $\theta =-\frac{\pi }{2}$
$x=r\cos \theta =2a\times \cos \frac{-\pi }{2}=0$
$y=r\sin \theta =2a\sin \frac{-\pi }{2}=-2a$
Thus, the Cartesian co-ordinates are $(0,-2a)$.