Question

Find the radius and the center of the circle.
Just check my answer.

Answer 1

(x-Cx)^2+(y-Cy)^2=r^2

Answer 2

2x^2 + 2y^2 - 2x + 2y + 7 = 0
My answer is :
c(1/2,-1/2) r= \[\sqrt{-7/2}\]

Answer 3

Am I right?
Cause I am having doubt that my answer is wrong because I have a negative radius

Answer 4

2x^2 + 2y^2 - 2x + 2y + 7 = 0

2x^2 - 2x + 2y^2 + 2y + 7 = 0

2(x^2 - x) + 2(y^2 +y) = -7

2(x^2 - x +(1/2)^2) + 2(y^2 +y+(1/2)^2) = -7 + 1

2(x-1/2)^2 + 2(y+1/2) = -6


its quite possible that this cannot produce a real circle; just becasue something has some numbers thrown about doesnt make it sensible :) lets chk the wolf

Answer 5

and make sure that aint spose to be a -7 instead

Answer 6

http://www.wolframalpha.com/input/?i=2x%5E2+%2B+2y%5E2+-+2x+%2B+2y+%2B+7+%3D+0

as is its right, but no circle

Answer 7

Check for typos:
Could the question be
2x^2 + 2y^2 - 2x + 2y = 7
or
2x^2 + 2y^2 - 2x + 2y - 7 = 0

Answer 8

That's why I am having doubts with my answer. :)
Maybe I just copied the text wrong.

Answer 9

If it is -7
will the answers be
c(1/2,-1/2) r=\[\sqrt{7/2}\]

Answer 10

??

Answer 11

if -7 then we get r^2 = 8 center: (1/2, 1/2)

Answer 12

-1/2 yeah, but r=sqrt(8) = 2sqrt(2)

Answer 13

did that wrong somehow, radius is 2 according to the wolf

Answer 14

http://www.wolframalpha.com/input/?i=2x%5E2+%2B+2y%5E2+-+2x+%2B+2y+-+7+%3D+0

Answer 15

r= (7sqrt(2))/2 ??

Answer 16

\[r^2=7+2(1/2)^2+2(1/2)^2\]

Answer 17

how did it became x = -3/2, x = 5/2 ???

Answer 18

i see what i did; we divide off the 2 and get 8/2 = 4 sqrt(4) = 2

Answer 19

your responses arent making sense to me

Answer 20

\[2(x^2 - x +(1/2)^2) + 2(y^2 +y+(1/2)^2) = 7 + 1\]
\[2(x-(1/2))^2 + 2(y+(1/2))^2 = 8\]
\[(x-(1/2))^2 + (y+(1/2))^2 = 4\]

Answer 21

those are points on the circle that the wolf handed out

Answer 22

2(x^2 - x +(1/2)^2) + 2(y^2 +y+(1/2)^2) = 7 + 1
Why did you add one on the right side of the equation?

Answer 23

becasue we add a total of 1 to the left side

2(1/2)^2 + 2(1/2)^2 = 1

Answer 24

2x^2 - 2x +2(1/2)^2 + 2y^2 +2y +2(1/2)^2) = 7 + 1

might be easier to see that way

Answer 25

i dont divide off the "2" right away which might be a difference in our computing techniques

Answer 26

ohh ok, I forgot adding the numbers that I added on the left side to the right side. That's why I got confused. :)
Anyway, I divided the equation directly to "2" but I still got the right answer. :)

Answer 27

thanks!