<p>How do you know when to use shell or washer method?</p>
<p>And how do you find which is the representative rectangle?! Any help would be greatly appreciated..</p>
<p>On the AP test there will be no questions that require the use of shells to solve the problem.</p>
<p>I’ve definitely seen multiple choice questions that required shell. I’m horrible at explaining, but I wanted to make sure that you didn’t believe the person above me. You will almost certainly get a free response question that will require disk or washer. I don’t know whether they ever put shell method questions on the free responses. I would reccommend googling it. It is going to be hard for anyone to really explain over a forum.</p>
<p>[Calculus</a> Videos](<a href=“http://www.math.armstrong.edu/faculty/hollis/calcvideos/]Calculus”>http://www.math.armstrong.edu/faculty/hollis/calcvideos/)
27 ~ 29</p>
<p>I have no seen any shells in the fRQ section…</p>
<p>according to the course outline, you are not supposed to have to know how to do the shell method. you are supposed to be able to use disk-washer.</p>
<p>HOWEVER, i have seen mc questions that are made much faster/easier by knowing how to do shell, esp with the ones that say “which of the following integrals could be used to calculate the volume.” </p>
<p>i would learn both. personally, i use shell whenever the revolution is around the y-axis, and disk-washer when the revolution is around the x-axis. my teacher made us do all of the frqs, and i didnt see a single one that required shell.</p>
<p>hope that helped, good luck</p>
<p>there arent any that NEED shells on AB, but they can be used.</p>
<p>for BC you should know shells.</p>
<p>You definitely are not required to use shells. There have been some questions where using shells are beneficial.</p>
<p>Shells used to be required until 1998, so if you have old MC questions, you might have seen some shells questions.</p>
<p>You don’t need to know shell and you can do all the shells with the washer method.</p>
<p>I thought my teacher accidentally skipped the topic on shells in class when i saw a chapter of it in my review book. I just spent so much time learning it and practicing it for no reason now. I just started studying for the AP test today so that was a huge waste of time. fmlll</p>
<p>There are no questions that will require shell method but it does make it easier instead of changing the orientation of the rectangles and changing everything to be in terms of the y variable instead of the x variable. Plus, you don’t run the risk of messing up the bounds because you forgot to change them to be in terms of y.</p>
<p>Great video links, Ren the SAT’er. Thanks a lot!</p>