Question

How do you differentiate `y^2 + x^2 = 9`?

Answer 1

I found:
`(dy)/(dx)=-x/y`

Explanation:

You can use implicit differentiation remembering that `y` is a function of `x`; so you get:
`2y(dy)/(dx)+2x=0`
`(dy)/(dx)=(-2x)/(2y)=-x/y`

Where `y=+-sqrt(9-x^2)`