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anonymous
 one year ago
I don't want anyone to give me the answer, I just need help understanding how to do it please!!
anonymous
 one year ago
I don't want anyone to give me the answer, I just need help understanding how to do it please!!

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0The general form of the equation of a circle is Ax2 + By2 + Cx + Dy + E = 0, where A = B 0. If the circle has a radius of 3 units and the center at (0, 4), which set of values of A, B, C, D, and E correspond to the circle? a)A = 0, B = 0, C = 2, D = 2, and E = 3 b)A = 1, B = 1, C = 8, D = 0, and E = 9 c)A = 1, B = 1, C = 0, D = 8, and E = 7 d)A = 1, B = 1, C = 8, D = 0, and E = 0 e)A = 1, B = 1, C = 8, D = 8, and E = 3

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1if we write the equation of a circle as x^2 + y^2 + 2gx + 2fy + c = 0 then the center is (g,f) and the radius is sqrt(g^2 + f^2  c) note there are no numbers before the x^2 and y^2 in the equation of a circle.

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1so for your circle you can see that A = 1 and B = 1

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0sorry im horrible at math. so do you substitute A and B for X and Y? and D and E for G and F?

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1if we write the 2 equations together we can compare x^2 + y^2 + 2gx + 2fy + c = 0 Ax^2+ By^2 + Cx + Dy + e = 0 can you see that A and B = 1?

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1note x^2 is same as 1x^2

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok, so would the answer be B?

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1we dont know that yet we need to find C D and E the center is at (0,4) meaning x = 0 and y = 4 if we compare this with (g,f) we see that g = 0 so C =0 Follow?

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1and in the case of y = 4 , f = 4 so f = 4 and 2f = 8 making D = 2f = 8

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1now to work out e(which = c) we need to solve radius r = sqrt(g^2 + f^2  c) 3 = sqrt(0^2 + (4)2  e)

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1so find e and you have your result

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh so its C. thank you for showing me how to do it

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1by writing the 2 equations together we can see that C  2g , D = 2f and E = c

welshfella
 one year ago
Best ResponseYou've already chosen the best response.1 that's called comparing coefficients
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