Question

Calculus help please
Solve the problem: The sales in thousands of a new type of product are given by s(t)=100-60e^-0.8t when t=3

I would think the s'(3)=144 thousand, but the answer is 4.4 thousand

Answer 1

\[\large\rm s(t)=100-60e^{-0.8t}\]\[\large\rm s'(t)=0-60e^{-0.8t}\cdot(-0.8)\]

Answer 2

Derivative of 100 is simply 0.
Maybe that's what was making your answer so large.
Hmm, forget chain rule also maybe?

Answer 3

I forget chain rule. Thank you