Determine two pairs of polar coordinates for the point (4, -4) with 0° ≤ θ

Question

Determine two pairs of polar coordinates for the point (4, -4) with 0° ≤ θ < 360°. 

A. (4 square root of 2, 45°), (-4 square root of 2, 225°)
B. (4 square root of 2, 135°), (-4 square root of 2, 315°)
C. (4 square root of 2, 225°), (-4 square root of 2, 45°)
D. (4 square root of 2, 315°), (-4 square root of 2, 135°)

thatonegirl_ · Answer

Polar coordinates are in the form (θ,r) and you have (x,y). Do you know how to find either theta or r given the rectangular coordinates you have?

ally_b · Answer

No, I'm confused

thatonegirl_ · Answer

Okay, so basically all you're doing is turning in your rectangular point (a point you can find on a normal x, y graph) into a polar coordinate (a circular looking graph).

thatonegirl_ · Answer

To find theta(θ), you can set up a tanθ=y/x. Just plug in your y and x that you are given and solve for theta

ally_b · Answer

so it would be tan^-1 (-4/4), which equals -45

thatonegirl_ · Answer

Yup! But since all of your answer choices are positive angles, how can you write -45 positively?

thatonegirl_ · Answer

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thatonegirl_ · Answer

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