Question

Solve the problem. Students in a math class took a final exam. They took equivalent forms of the exam in monthly intervals thereafter. The average score S(t), in percent, after t months was found to be given by 6) - 70-20In (t.1). *20. Find Slu). 20 OSTU - 70 STO OSD- t + 1 20 0 st) SO) = -20 In

Answer 1

Find the derivative of S(t)=70-20ln(t+1)

$\begin{gathered} \frac{dS(t)}{dt}=0-20\cdot\frac{1}{t+1}\cdot1 \\ \frac{dS(t)}{dt}=\frac{-20}{t+1} \\ \end{gathered}$

The derivative is -20/t+1