Thread: cartesian and polar

Hello,

I need help with this question,

a) express in polar co-cordinates the cartesian co-ordinates (2, -6)

b) express in cartesian co-ordinates the polar co-cordinates (3, 150degrees)

Thank you.

Originally Posted by simon

Hello,

I need help with this question,

a) express in polar co-cordinates the cartesian co-ordinates (2, -6)

b) express in cartesian co-ordinates the polar co-cordinates (3, 150degrees)

Thank you.

For these types of problems you need to recall that:



Inverting these relations gives:



So for question a)
(2,-6) => x = 2, y = -6



is a reference angle. The point (2,-6) is in the 4th quadrant, so your angle measured from the +x axis is 360 - 71.5651 = 288.435 degrees.

Thus: (2,-6) => (2sqrt(10), 288.435 degrees).

For question b)
(3, 150 degrees) => r = 3, = 150 degrees



Thus: (3, 150 degrees) => (-2.59808, 1.5).
(And note that it is, in fact, in the second quadrant as the original coordinates state.)

-Dan