Question

What is the value of b for the following circle in general form?
x^2+y^2+ax+by+c=0

Answer 1

The center of this particular circle is (1,-2)

so h = 1 and k = -2

Answer 2

the radius is 3, so r = 3

Answer 3

plug these values into (x-h)^2 + (y-k)^2 = r^2 and try to get the equation into the form x^2+y^2+ax+by+c=0

Answer 4

\[(x-1)^{2}+(y+2)^{2}=\sqrt3\]
I'm not really sure how to get it into that form. >~<

\[x^{2}+2y^{2}+x+2y+3=0\]? ;-;

Answer 5

notice how 'by' can only come from expanding out (y+2)^2

so you just need to expand that out using FOIL

Answer 6

y+2 y+2?

Answer 7

(y+2)(y+2) = ??

Answer 8

Yea that

Answer 9

WAIT

Answer 10

Sorry, AFK

\[y^{2}+4y+4\]?

Answer 11

so by = 4y which means b = 4

Answer 12

:O And that's my answer... c: ?

Answer 13

yes it is

Answer 14

Ahh. Thank yhu! ^_^

Answer 15

you're welcome