Find the corresponding rectangular coordinates for the point.

1. Jan 5, 2014

Lebombo

1. The problem statement, all variables and given/known data

Find the corresponding rectangular coordinates for the point. (-2, $\frac{5\pi}{3}$)

x = -2cos($\frac{5\pi}{3}$)

x = -2cos($\frac{2\pi}{3}$)

x = -2* $\frac{-1}{2}$ = 1

y = -2sin($\frac{5\pi}{3}$)

y = -2sin($\frac{2\pi}{3}$)

y = -2*$\frac{\sqrt{3}}{2}$ = -$\sqrt{3}$

So the coordinate is (1, -$\sqrt{3}$)

This is my conclusion, however, the answer I found online does not agree: (1, -2)

Am I incorrect? If so, what am I not doing correctly?

2. Jan 5, 2014

LCKurtz

I assume that is in polar coordinates, with negative radius.

Are you sure those are equal?

Same problem. Are you sure those are equal?

That online answer is wrong. Fix your signs and you will have it.

3. Jan 5, 2014

Lebombo

Yes, I should have mentioned the type of coordinates.

x = -2cos($\frac{5\pi}{3}$)

x = 2cos($\frac{2\pi}{3}$)

x = 2* $\frac{-1}{2}$ = -1

y = -2sin($\frac{5\pi}{3}$)

y = 2sin($\frac{2\pi}{3}$)

y = 2*$\frac{\sqrt{3}}{2}$ = $\sqrt{3}$

So the coordinate is (-1, $\sqrt{3}$)

Like this?

4. Jan 6, 2014

Tanya Sharma

Yes...(-1,√3) is the correct answer .