Question

How do you find the derivative of `y=1/(1+e^x)`?

Answer 1

`dy/dx=-e^x(1+e^x)^-2`

Explanation:

Differentiate using the chain rule
Given `y=f(g(x))`
`dy/dx=f'(g(x))*(g'(x)) larr`chain rule
`y=(1+e^x)^-1`
`dy/dx=(-(1+e^x)^-2)*e^x`
`=-e^x/(1+e^x)^2`