Question

Which set of polar coordinates describes the same location as the rectangular coordinates (1,-1)?

A. (-1, 135 degrees)
B. (sqrt(2) , 315 degrees)
C. (1, 45 degrees)
D. (sqrt(2) , 225 degrees)

***My Answer: A***
Is this correct?

Answer 1

B

Answer 2

Why is that?

Answer 3

r is sqrt(2).
positive r and -45 degrees or +315 degrees.
use negative r and 135 degrees.

Answer 4

B is initially correct:)

Answer 5

\[r ^{2}=x ^{2}+y ^{2}\] so, \[1^{^{2}}+(-1)^{2})=r ^{2}\]\[r=\sqrt{2}\]

Answer 6

Oh I see now! Thank you guys for the help : )

Answer 7

\[\tan^{-1} \frac{ -1 }{ 1 }=45\] subtract 45 from 360 u get 315

Answer 8

Ohhh that's what I was doing wrong. Thanks for helping me understand!