Find the corresponding rectangular coordinates for the point.

[Lebombo]

Homework Statement

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?

 

[LCKurtz]

Homework Statement

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

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

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

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

Are you sure those are equal?

x = -2* \frac{-1}{2} = 1
y = -2sin(\frac{5\pi}{3})

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

Same problem. Are you sure those are equal?

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)

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

 

[Lebombo]

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

Yes, I should have mentioned the type of coordinates.

Fix your signs and you will have it.

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?

 

[Tanya Sharma]

Yes...(-1,√3) is the correct answer .