Help?
Determine two pairs of polar coordinates for the point (5, -5) with 0° ≤ θ

Question

Help?
Determine two pairs of polar coordinates for the point (5, -5) with 0° ≤ θ < 360°.

anonymous · Answer

@mathmale ?

anonymous · Answer

|dw:1398470980793:dw|

anonymous · Answer

$r=\sqrt{x^2+y^2}$ and it is pretty obvious in this case that on possible value for $\theta$ is $-45$ since you appear to be working in degrees

anonymous · Answer

since you need something between 0 and 360, add 360 to -45

anonymous · Answer

Where did you get -45?

anonymous · Answer

@whpalmer4

whpalmer4 · Answer

|dw:1398488882918:dw|

$$\tan \theta = \frac{5}{-5} = -1$$For what value of $\theta$ does $\tan \theta = -1$?  Looking at the triangle with its two equal legs ought to be a pretty good clue :-)

anonymous · Answer

I have no idea..

whpalmer4 · Answer

|dw:1398553278657:dw|

Isn't that an isosceles triangle?  If so, what are the angles?

whpalmer4 · Answer

@This_Is_Batman still no idea?  This is a right triangle which is also an isosceles triangle.  What does that imply about the two unknown angles?  |dw:1398786630140:dw|


Just as a precaution, let me point out that in my diagram, I have labeled the length of each leg as 5, NOT the hypotenuse, despite the way that OS is displaying it when I look at it!  Bad, bad, bad, OpenStudy!