Question

Convert
(-5, pi/4)
to rectangular coordinates.

A. (sqrt(2) / 2, sqrt(2) / 2)
B. (5 sqrt(3) / 2, 5/ 2)
C. (5 sqrt(2) / 2, 5 sqrt(2) / 2)
D. (-5 sqrt(2) / 2, -5 sqrt(2) / 2)

Answer 1

I am thinking that it would be B. However I am having trouble understanding how to get my answer.

Answer 2

\[x = rcos \theta\]\[y= rsin \theta\]

Answer 3

\[x = (-5)\cos(\frac{ \pi }{ 4 })\]\[y = (-5)\sin(\frac{ \pi }{ 4 })\]

Answer 4

I don't get any of the answers :(

Answer 5

yes. last step is to use a unit circle to get sin (π/4) and cos (π/4)

Answer 6

45?

Answer 7

Oh sin and cos of 45?

Answer 8

yes

Answer 9

It would be A?

Answer 10

D.
A doesn't have -5 for r

Answer 11

Oh you just said the answer didn't you

Answer 12

yes r can be negative.