Question

w=Cr^-2 solve for r

Answer 1

w = Cr^-2
w = C/r^2
wr^2 = C
r^2 = C/w
r = +/- sqrt (C/w)
Check mu work.

Answer 2

i came up with r=sqrt of C/w
what is the +/- for ? could it be either positive or negative?

Answer 3

ANYTIME you take the square root of something, you get a + or -. Let me show you why.
Take the square root of 4. That is 2. Now if we multiply +2 x +2 we get +4. BUT if we multiply -2 x -2 we also get +4. So the square root of 4 is +/- 2. Same with anything else because a minus number x a minus number = a + number.