Implicit differentiation to find the slope

[fishingspree2]

Homework Statement

$$(x - h)^2 + (y - k)^2 = r^2$$
where h,k and r are constants

The Attempt at a Solution

$$\begin{array}{l}<br /> \frac{d}{{dx}}\left[ {(x - h)^2 + (y - k)^2 } \right] = \frac{d}{{dx}}r^2 \\ <br /> 2(x - h) + 2\frac{{dy}}{{dx}}(y - k) = 0 \\ <br /> \Rightarrow \frac{{dy}}{{dx}} = - \frac{{(x - h)}}{{(y - k)}} \\ <br /> \end{array}$$

Is my work correct?
Thank you

 

[rootX]

looks good to me =P

 

[Defennder]

Yeah it seems all right.