Posted by mazoe on Monday, February 27, 2012 at 3:50am.
Given that the equation of the circle is x^2 + y^2 +2x 8y+5 =0
(i)Find the centre and radius of the circle
(ii)Determine whether the line x3y=8 is tangent to the given circle

maths  Henry, Wednesday, February 29, 2012 at 3:49pm
1. x^2+2x+(2/2)^2+Y^28y+(8/2)^2=5+1+16.
X^2+2x+1 + Y^28y+16 = 12.
(x+1)^2 + (y4)^2 = 12.
(xh)^2 + (yk)^2 = r^2.
C(h,k).
C(1,4).
r^2 = 12.
r = 2*sqrt3 = 3.46.