Derivative of exponential function

[SheldonG]

Homework Statement

find y', $$y = \frac{e^x}{1+e^x}$$

Homework Equations

derivative of e^x = e^x, quotient rule.

The Attempt at a Solution

The old man is back, sorry, and I don't seem to be able to enter this using the tex stuff.
This is from Kline's Calculus, page 348. I proceed as follows:

y' = [(1+e^x)(e^x)-e^x(e^x)]/(1+e^x)^2 --- the quotient rule.

Simplifying:

y' = e^x/(1+e^x)^2

However, Kline gives 1/(1+e^x).

I am at a loss. Thanks for any suggestions.

Sheldon

 

[mjsd]

I believe your answer is correct

 

[Gib Z]

You can check on www.calc101.com, it shows how derivatives are done. Your answer is correct, Klines books weren't very well edited >.<

 

[SheldonG]

Thank you both very much. Also for the calc101 link.

Sheldon