Calculus
The following formula accurately models the relationship between the size of a certain type of a tumor and the amount of time that it has been growing:
V(t)=400(1-e^ -.0024t)^3

where t is in months and V(t) is measured in cubic centimeters. Calculate the rate of change of tumor volume at 100 months.

The correct answer is 0.103 cm^3 month
but, how is this arrived at?

Question

Calculus
The following formula accurately models the relationship between the size of a certain type of a tumor and the amount of time that it has been growing:
V(t)=400(1-e^ -.0024t)^3
 
where t is in months and V(t) is measured in cubic centimeters. Calculate the rate of change of tumor volume at 100 months.

The correct answer is 0.103 cm^3  month
but, how is this arrived at?