Find the rectangular coordinates of the point whose polar coordinates are (-3,5 pi/3).

a.) (1/2,-sqrt(3)/2)
b.) (-1/2, sqrt(3)/2)
c.) (-3/2,3 sqrt(3)/2)
d.) (3/2,-3 sqrt(3)/2)

Question

Find the rectangular coordinates of the point whose polar coordinates are (-3,5 pi/3).
 	
a.) (1/2,-sqrt(3)/2)
b.) (-1/2, sqrt(3)/2)
c.) (-3/2,3 sqrt(3)/2)
d.) (3/2,-3 sqrt(3)/2)

mathmale · Answer

In your shoes, I'd draw this situation.   Have you tried doing that?

anonymous · Answer

i dont understand how to do it.

mathmale · Answer

I'd suggest you draw a circle of radius 3.  Then, draw on this same graph the angle 5pi/3 (300 degrees).

zepdrix · Answer

If you're having trouble drawing it out ( I know that understanding trig conceptually can be difficult ) then you can trust in your identities for converting from polar to Cartesian.

$$\Large\bf\sf x=r \cos \theta$$$$\Large\bf\sf y=r \sin \theta$$And we were given the point,$$\Large\bf\sf (r,\theta)\quad=\quad \left(-3,\frac{5\pi}{3}\right)$$

zepdrix · Answer

Just plug the r and theta into the formulas and simplify.

anonymous · Answer

okay.

zepdrix · Answer

Oh I guess you still have to remember your special angles like cos(5pi/3)
:3

anonymous · Answer

yeah, I got it. Thank you so much.

zepdrix · Answer

Oh good! :)