What is the slope of the tangent line of 1/(e^y-e^x) = C 1eyex=C, where C is an arbitrary constant, at (-2,1)(2,1)?

1 Answer
Aug 6, 2016

The slope is 1/e^31e3.

Explanation:

This will be easier rewritten as:

(e^y-e^x)^-1=C(eyex)1=C

Now, we can use implicit differentiation (remember that each occurrence of yy will put the chain rule in effect):

-(e^y-e^x)^-2*d/dx(e^y-e^x)=0(eyex)2ddx(eyex)=0

-1/(e^y-e^x)^2(e^y*dy/dx-e^x)=01(eyex)2(eydydxex)=0

(e^x-e^y(dy/dx))/(e^y-e^x)^2=0exey(dydx)(eyex)2=0

So, we want to solve for dy/dxdydx when (x,y)=(-2,1)(x,y)=(2,1).

(e^-2-e^1(dy/dx))/(e^1-e^-2)^2=0e2e1(dydx)(e1e2)2=0

Cross-multiplying:

1/e^2-e(dy/dx)=01e2e(dydx)=0

dy/dx=1/e^3dydx=1e3