Question

find the derivative of f(t)=e^-kt cos(ln(t))

is this correct e^(-kt)*-t*sin(ln(t))(1/t)?

Answer 1

In google paste:

Derivative online

When you see list of results click on:

Online Derivative Calculator with Steps - eMathHelp

When page be open in rectangle Function type your function.

In rectangle Variable type t

Then click option CALCULATE

You will see the solution step-by-step.

Answer 2

e^(-kt) cos(ln(t))
using the product rule, the derivative would be
-k e^(-kt) cos(lnt)) + e^(-kt) (-sin(lnt)) * 1/t
= -e^(-kt) (k sin(lnt) + 1/t cos(lnt))