I got the answer of about 4872 calcs and I want to be sure that I did it correctly.

Rate of calculators produced

dx/dt=5000(1-(100/(t+10)^2)

Find how many are made from the beginning of the 3rd to the end of the 4th week.

I took the derivative and got 5000(x^2+10x+100)/x+10 and took it from 3 to 5...is that process right?