I need help with the first part of this problem. I got 3 but the answer is 24. What did I do incorrectly? [ File > http://lhh.tutor.com/SharedSessionFiles/6994427b4e2442c4902b336cde386e3c_002.jpg ]
Tutor.com

In this video, Salman Khan of Khan Academy explains definite integrals. Part 4 of 5.
Khan Academy

A helpful scientific calculator that runs in your web browser window.
Holt Online Learning

Excellent site showing examples of algebra, trig, calculus, differential equations, and linear algebra.
Paul's Online Math Notes

This calculus integral reference sheet contains the definition of an integral and the following methods for approximating definite integrals: left hand rectangle, right hand rectangle, midpoint rule, trapezoid rule, and Simpson’s rule. There is a list of many common integrals. Also included in this reference sheet is nice table for trigonometric substation when using integrals. Integration by substitution is defined as well as the integration by parts.
eCacl.com

Very extensive help sheet that contains everything from simple derivative/integration formulas, to quick explanations of advanced derivation and integration techniques.
Pauls Online Math Notes

Several examples and tutorials dealing with integral calculus
Pauls Online Math Notes

find the volume of the solid formed by revolving around the xaxis.
Tutor.com

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=4000(1100/(t+10)^2) calculators/week. (Notice that production approaches 4000 per week as time goes on, but the initial 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 fourth week. (Round your answer to the nearest calculator.)
Tutor.com

use the integral evaluation theorem to solve
Tutor.com
