1. The problem statement, all variables and given/known data Alabama Instruments Company has set up a production line to manufacture a new calculator. The rate of production of these calculators after t weeks is (dx/dt)=4,500[1-130/(t+9)^2] calculators per week. Production approaches 4,500 per week as time goes on, but the intial production is lower because of the workers' unfamiliarity with the new techniques. Find the number of calculators produced from the beginning of the third week to the end of the forth week. Round the answer to the nearest integer. 2. Relevant equations Anti-derivative formula... F(a)-F(b)= integral of f(x)dx within interval [a,b] 3. The attempt at a solution So what I am confused about is whether my answer is wrong, or the book is wrong since I have tried the problem over 10 times and I keep getting the same answer which is 750. The book says the answer is 818. Here's what I tried: I just took the integral of (dx/dt) and put it over the interval of [3,4] which led me to the answer of 750. I'm really lost on this problem and any help would be extremely appreciated. Thanks!