## agentx5 3 years ago Converting Cartesian coordinates into polar coordinates. (x,y) = (3,-5) (r,$$\theta$$) = ($$\sqrt{34}$$,???) $$r=\sqrt{(3)^2+(-5)^2}=\sqrt{9+25}=\sqrt{34}$$ $$\theta = tan^{-1}(\frac{(-5)}{(3)})=???$$ My answer needs to be in radians an I'm not seeing how the unit circle is going to be of much help here. It's not a nice angle like $$\frac{\pi}{2}$$, $$\frac{\pi}{3}$$, $$\frac{\pi}{4}$$, $$\frac{\pi}{6}$$, or $$\pi$$

1. annas

-59.036

2. agentx5

I don't think it's going to let me take it as a decimal though, especially since is a irrational, non-repeating decimal: http://www.wolframalpha.com/input/?i=tan^%28-1%29+%28-5%2F3%29

3. annas

it will be most probably $-\pi/3$

4. agentx5

I was hoping Wolf would help me convert, but alas it appears not... |dw:1342210050046:dw|

5. agentx5

Actually that's fairly close annas The actual value is -1.030376827... (radians) -$$\frac{\pi}{3}$$ is -1.047197551... (radians)

6. annas

yes

7. agentx5

Let me see if it takes it after I do the rest of the problem, if it does, you getz a cookie :-3

8. agentx5

$\frac{-\pi}{3} \rightarrow \frac{5\pi}{3}$ Yes? And... ($$\large-\sqrt{34},\frac{2\pi }{3}$$) is the valid r<0 value, yes?

9. agentx5

I don't know what they were expecting here. It's not quite a 3-4-5 triangle here, the 5 is on the opposite side, not the hypoteneuse

10. agentx5

Proof that I can't make this stuff up, and that it's the only one for this part giving me issues:

11. annas

12. agentx5

But it's not correct yet m'dear! ^_^

13. agentx5

*meep*

14. annas

yap thats why i said "eat cookies now !!!!"

15. agentx5

*idea* I'm going to try 180/$$\pi$$ to convert and see if I can recognize it

16. annas

okey then goodluck