this is what we call "completing the square" in math
first we gather up the x terms
x^2 - 4x
then we take the b -term, divide it by 2, square it, then add it to both sides of the equation
x^2 - 4x + 2 + {the y terms but they're not important right now} = 10 + 2
then we factor x^2 - 4x + 2 = (x-2)^2
making h = 3
Join the QuestionCove community and study together with friends!
Sign Up
zarkam21:
-4.5
Vocaloid:
i'm not sure that's right
y^2 + by + c = (y+2)^2 (this is taken from the circle equation), c is just some constant that's not important to solving the problem
so
y^2 + by + c = y^2 + 4y + 4
meaning b = 4
a is just a normal circle w/radius 1
b is not a circle, it's a line
c is not a circle (at least not in the real plane, it exists in the imaginary plane only)
so d, since this is a point
Still Need Help?
Join the QuestionCove community and study together with friends!
crap lemme just teach myself this again real quick
Still Need Help?
Join the QuestionCove community and study together with friends!
Sign Up
zarkam21:
OKay
Vocaloid:
|dw:1517595560710:dw|
Vocaloid:
first find the midpoint of the two vertices, that will give you the center
zarkam21:
midpoint is (2,2)
Vocaloid:
good, and each foci is 3 units away from the center so c = 3
the two vertices are the endpoints of the major axis, so the major axis is 14 units long, making a = 14/2 = 7
c^2 = a^2 - b^2
3^2 = 7^2 - b^2 making b^2 = 40
putting this all together:
Still Need Help?
Join the QuestionCove community and study together with friends!
Join the QuestionCove community and study together with friends!
Sign Up
zarkam21:
@Vocaloid
zarkam21:
@Vocaloid
Vocaloid:
if we do a quick sketch, we can see that the foci + vertices line up on the y-axis
the midpoint is (0,0) using the midpoint of the two vertices
meaning the vertices are 4 units apart from the midpoint
so the a term is 4 meaning the y^2 term has to have 4^2 = 16 below it
making B the only possibility
Vocaloid:
also this q is getting laggy can we open a new one