Question

The number of people who donated to a certain organization between 1975 and 1992 can be modeled by the equation
D(t)=-10.61t^(3)+208.808t^(2)-168.202t+9775.234 donors, where t is the number of years after 1975. Find the inflection point(s) from t=0 through t=17 , if any exist.


a. There are no inflection points from t=0 through t=17 .

b. There is one inflection point at t=6.56.

c. There are inflection points at t=0 and t=17.

d. There is one inflection point at t=0.15.

e. There are inflection points at t=0, t=0.15,and t=17.

I thought it was B.

Answer 1

An inflection point is a point on a curve at which the second derivative changes sign. You must find point where second derivative = 0

Go on:

wolframalpha dot com


When page be open in rectangle type:

second derivative of -10.61t^(3)+208.808t^(2)-168.202t+9775.234

and click option =

When you see result click option:

Show steps

Then in rectangle type:

solve 417.616-63.66t=0


Inflection point is:

t=6.5601

Answer 2

Thanks, i thought it was B. your awesome.