im curious as to why ur looking at (y-2)²...?
My question asks "Give the equation of a circle with center (1, 2), radius 3"
and the genral equation for a circle is "(x - a)² + (y - b)² = r²"
hence (y - 2)².
From that question, the book states that the answer is;
(x - 1)² + (y - √2)² = 3
expanded
x² - 2x + y² - 2√2y = 0
very bizarre!
]]>the equation u have is indeed correct..
im curious as to why ur looking at (y-2)²...?
the x²-2x can be simplified to x(x-2)
so:
x(x-2) +y²-4y=4
what it seems you're doing is saying (y-2)² = y²-4y+4.. which is true..
however what you have in this equation is:
x(x-2) = -y²+4y+4
which using the quadratic formula forms:
y=1±√2
so you have x(x-2) = (y-[1+√2])(y-[1-√2])
or aternatively:
x(x-2) = (y-[1+√2])(y+[√2-1])
]]>expanded:
x² - 2x + 1 + y² - 4y + 4 = 9
and
x² - 2x + y² - 4y = 4?
my book is saying (y - 2) (y - 2) = y² - 2√2y!
(y - 2) (y - 2) = y² - 2y - 2y + 4 in my eyes?!