Sorry for not using LaTeX, I'm not used to it yet, but I promise I would improve, so the equation is:

Let f(x)= 6tan^(-1)(4e^(x). Need to find the derivative

I continued to solve the equation, before differentiating f(x) = y = 6(1/(tan(4e^(x))) = 6cot (4e^(x)),

Now, ln y = ln (6cot (4e^(x))) =>

ln y = ln 6 + ln(cot(4e^(x))) =>

y’/y = (1/6) + (1/ cot(4e^(x))) *(- csc^(2) (4e^(x)))*(4xe^(x-1))) =>

y’/y = (1/6) - [(4xe^(x-1))*(csc^(2)(4e^(x)]/[cot(4e^(x)], and =>

y’ = 6cot (4e^(x)) * {(1/6) - [(4xe^(x-1))*(csc^(2)(4e^(x))]/[(cot(4e^(x))]},

I definitely have some problems with log functions, I think...

Thank you