(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

find y', [tex] y = \frac{e^x}{1+e^x}[/tex]

2. Relevant equations

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

3. 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

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# Derivative of exponential function

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