Rectangular coordinates: (0,-6)

Show me how to find the polar coordinates for this please.

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- Oct 2nd 2012, 11:58 PMTWNRectangular to polar coordinate conversion
Rectangular coordinates: (0,-6)

Show me how to find the polar coordinates for this please. - Oct 3rd 2012, 12:18 AMProve ItRe: Rectangular to polar coordinate conversion
Well you have not moved across at all, and gone down 6 units. Surely you can read off what the magnitude is. As for the angle, if you started from the positive x axis and went anticlockwise, what angle is swept out?

- Oct 3rd 2012, 12:31 AMTWNRe: Rectangular to polar coordinate conversion
- Oct 3rd 2012, 12:32 AMProve ItRe: Rectangular to polar coordinate conversion
- Oct 3rd 2012, 12:38 AMTWNRe: Rectangular to polar coordinate conversion
- Oct 3rd 2012, 12:51 AMProve ItRe: Rectangular to polar coordinate conversion
It's either $\displaystyle \displaystyle \begin{align*} \frac{3\pi}{2} \end{align*}$ if you move anticlockwise, or $\displaystyle \displaystyle \begin{align*} -\frac{\pi}{2} \end{align*}$ if you move clockwise. Generally we define $\displaystyle \displaystyle \begin{align*} \theta \in (-\pi, \pi] \end{align*}$, so choose $\displaystyle \displaystyle \begin{align*} -\frac{\pi}{2} \end{align*}$.

Now what is r? - Oct 3rd 2012, 01:03 AMTWNRe: Rectangular to polar coordinate conversion
Would it be 6 or -6?

- Oct 3rd 2012, 01:34 AMProve ItRe: Rectangular to polar coordinate conversion
r represents the magnitude, magnitudes can never be negative.