
Stanton D. answered 01/15/20
Tutor to Pique Your Sciences Interest
Hi Crystal F.,
So what do you need to do to get velocity from position? If your answer is, differentiate once with respect to time, you are right (so far!).
So -- how do you differentiate exp(cos(x)) with respect to t? Answer: you don't. Somewhere in there, someone messed around with a variable; I think what is intended is s(t) = exp (cos(t) ) ? [Else, you don't have any logical connect between s and t! And s can't be a function of itself! ]
Now (assuming you take that correction!) you have a differentiable form. Result d(s)/dt = exp (cos(t)) * (-sin(t)). If you want that to equal 0 , only one of the terms of that product can do that. Which one? And once you know that, you can cherry-pick the velocity-zero positions from the t (axis) for the sin function.
--Cheers, -- Mr. d.