hey

I have done part a) of the question which need checking & need help on part b)

a) Find the centre and radius of the following circle:

2x^2 + 2y^2 + -4x + 10y = 8

radius = 3.3 centre = (1, -2.5) << this is what i got

b) Find the equation of the tangent to the circle when the circle intersects the x-axis in the positive quadrant.

The derivative of the following

f(x) = Square root((x+1)/(x-1))

I know the answer to this.. which is -1/2(x+1)^1/2 (x+1)^-3/2

Do not know how to get to the answer, gets abit confusing when i applied the quotient rule as my numerator was zero but don't know if I was doing it right.