# Calculus: Other Calculus Problems – #28140

Question: Union membership as a percentage of the total labor force can be modeled by

$M\left( x \right)=0.0002{{x}^{3}}-0.049{{x}^{2}}+3.75x-68$

where M is the membership as a percentage of the total labor force and x is the number of

years after 1900. Find the rate at which the membership is changing in 1980.