1. ## related rates

if xy^2=12 and dy/dx=6, find dx/dy when y=2

2. If we differentiate $y^{2}=\frac{12}{x}$ we get, $2y\frac{dy}{dx}=\frac{-12}{x^{2}}$.

Can you substitute values in to get our answer?

3. Originally Posted by ANDS!
If we differentiate $y^{2}=\frac{12}{x}$ we get, $2y\frac{dy}{dx}=\frac{-12}{x^{2}}$.

Can you substitute values in to get our answer?

so would it look like this:

6=-12/4x^2?
if i solve for x... i dont get the same answer as they have in the text book

4. I didn't see that first line: They want you to differenciate Y with respect to X, and X with respect to Y? o_0 Have you written the problem correctly? I am referring to this part here:

dy/dx=6, find dx/dy
What is the answer they give you in the book?

5. Originally Posted by ANDS!
I didn't see that first line: They want you to differenciate Y with respect to X, and X with respect to Y? o_0 Have you written the problem correctly? I am referring to this part here:

What is the answer they give you in the book?

yes, the question is correct.. the one above
if xy^2=12 and dy/dx=6, find dx/dy when y=2
the answer they have is -18