Question

Find the derivative of the function.

y=(e^3u -e^-3u)/(e^3u+e^-3u)

Answer 1

the easy way is to notice that this is just

y = tanh(3u)
y' = -3sech^2(3u)

or, using the exponentials, that's

12/(e^3u + e^-3u)^2
or
(12e^6u)/(e^6u + 1)^2