# Thread: How to get a slope?

1. ## How to get a slope?

Hi all:

I have a stupid question: can I get dy/dx from f(x,y)=c without solving it (c is a constant). Can I take partial derivative with respective x for both sides to get dy/dx?
More specific, my equation is 1/xy+1/(1-y)=c. Or is there a better way to get dy/dx at two solutions?

Thanks!

Simon

2. Originally Posted by simonwei
Hi all:

I have a stupid question: can I get dy/dx from f(x,y)=c without solving it (c is a constant). Can I take partial derivative with respective x for both sides to get dy/dx?
More specific, my equation is 1/xy+1/(1-y)=c. Or is there a better way to get dy/dx at two solutions?

Thanks!

Simon
I don't really understand your question but this may be what you are looking for.

$\frac{dy}{dx}=-\frac{\frac{\partial f}{\partial x}}{\frac{\partial f}{\partial y}}$