<p>For that problem, check if -5 makes the function undefined.</p>
<p>It doesn't, so if you plug in -5, you get the limit, which is -7</p>
<p>If it DOES make it undefined, such as (limit x --> -1) OF:</p>
<p>(x^2 - 1)/(x + 1)</p>
<p>Then you have to factor:</p>
<p>(x+1)(x-1)/(x-1)</p>
<p>Cross out the x-1 's and plug in.</p>
<p>^ For anyone who's taken calc and who's lazy, L'hopital will take some time off solving limits. However, you must have a 0/0 or +-inf/+-inf from direct substitution to use it.</p>
<p>^ I love L'Hopital's rule</p>
<p>I used cylindrical shell method to solve a volume of rotation problem on a RUSH test.</p>
<p>ALl you needed was the formula for the area of a cone, but... why do geometry? It's not as fun.</p>
<p>its faster than the shell method.
they gave me a hard time, not because i didn't understand them, because i went on a band field trip for a WEEK! lol.</p>
<p>I don't know... integrate 2<em>pi</em>x*f(x), or use the formula.</p>
<p>Actually the shape it made was more complicated than just a cone, so I would have had to use two steps.</p>
<p>I just really don't like geometry. Lucky me that I have to take the subject test with a bunch of geometry.</p>
<p>To Sixthsense </p>
<p>I owned a 2007-08 PR and checked out a 2003 PR at my school library. There is no difference between two books except 2003 sugessted using notecards and a few practice test questions were removed and added differently.</p>
<p>How to solve magnitude/ vector problems</p>
<p>If the magnitude of vectors x and y are 13 and 4, respectively, then the magnitude of (x-y) could not be
a)17 b)13 c)11 d)9 e)4</p>
<p>E is the answer BTW</p>
<p>If the magnitude of vectors v and (w+v) are 7 and 20, respectively, then the magnitude of will be
*this one I making it up but I sorta remember this one on some other test</p>
<p>I'm also struggling with question that are logic. I keep being stressed about the question they are asking. PR and sparknotes said the same method in solving this but its still been bugging me. So anyone know to solve them?</p>
<p>When people are referring to Barrons being difficult are they talking about the 1st book or the 2nd book shown below:</p>
<p>Amazon.com:</a> How to Prepare for the SAT II Math Level II C: Howard Dodge, Richard Ku: Books</p>
<p>I know the test questions in the 2nd book are hard, is the 1st book also the same level of difficulty for questions? </p>
<p>Or is PR THE book for everything - review and practice tests?</p>
<p>^ I'm pretty sure people are referring to the second book shown. Rule of thumb: If it says SAT II on the front cover, it's probably out of date. They're formally known as the SAT Subject Tests, and that's what will be in the title. </p>
<p>PR is good, but Barrons over prepares you, which is good if you've mastered all the other books. </p>
<p>Quick question. How do I solve:</p>
<p>*If the 20th term of an arithematic sequence is 100, and the 40th term is 250, what is the first term? *</p>
<p>I was taught to divide their explicit formulas by each other, solve for d, then solve for a1. I know it works for geometric sequences, but it never works out when I try it on an arithematic sequence.</p>
<p>An = a + (n-1)d</p>
<p>A20 = 100
A40 = 250</p>
<p>so if we pretend A20 is the first #:
A1 = 100
A21 = 250
N = 21
d = ?
so we solve for d:</p>
<p>An = a + (n-1)d
250 = 100 + (20)d
150 = 20 d
d = 15/2 <--we can do this b/c d will be the same for the entire arithmetic sequence.</p>
<p>then we go back to our original numbers:
A20 = 100
A = ?
d = 15/2
n = 20</p>
<p>An = a + (n-1)d
100 = a + (19)(15/2)
200/2 = a + (285/2)
200/2 - 285/2 = a
a = -85/2 *******</p>
<p>I'm not normally good at math... do you know if that's the answer you're supposed to get?</p>
<p>I've got a couple questions.</p>
<p>First off, when you're describing coordinate points, do you always describe them as (X,Y)? My RUSH book told me that my answer was wrong for a parabola question in which the independent variable was y, not x, and the graph opened out horizontally. I answered by naming the vertex as (1, -5), because it was supposed to be 1 on the x-axis and -5 on the Y-axis. However, the answer explanation said that I was supposed to answer it like (-5, 1).</p>
<p>Here's my other question: When you have Y^2= 16, it becomes Y= + or - 4</p>
<p>If you have X = 9^1/2 (that's supposed to be a square root sign), does it also equal to + or - 3, or is it just positive 3? I thought it was supposed to be the former, but my RUSH book says otherwise...</p>
<p>X is the independent variable..
domain is what goes in (independent or x)
but what comes out is dependent on what the independent is. so this is (y)</p>
<p>when you have a sqrt of something, it will always be +/-, but for math iic, it's gonna be the +, why i dont know. i have not encountered a problem asking for the - value, but i could be wrong.</p>
<p>Yea, RUSH is confusing me a bit on these little things such as how we'll be supposed to represent coordinates on the CB test...</p>
<p>It's great prep, though. I really need to work on the little mistakes, as that book tends to get a lot of errors out of me...</p>
<p>
[quote]
If the magnitude of vectors x and y are 13 and 4, respectively, then the magnitude of (x-y) could not be
a)17 b)13 c)11 d)9 e)4
[/quote]
</p>
<p>When you're subtracting vectors, the resulting vector must be greater than the smaller vector.</p>
<p>Has anyone used the Kaplan's book to prepare? I am getting around 730-750 on their practice tests....can I expect a similar score on actual test day?</p>
<p>so i was looking through some sample prblms in the CB book and i ran across one that contained 'least-squares exponential regression'? can anyone xplain what this is? iv never heard of it before. thanks</p>
<p>^ That's one of the most difficult types of problems you'll see on the test. If you have the free booklet on SAT II's, there's that type of problem in there and CB explains it.</p>
<p>Least squares regression? That's a calculator task.
Enter the first set of data into list 1, enter the second set of data into list 2. go to stat->calc->ExpReg L1, L2. </p>
<p>Bam. Done.</p>
<p>Has anyone used the Kaplan's book to prepare? I am getting around 730-750 on their practice tests....can I expect a similar score on actual test day?</p>
<p>I have the same question. I got a 760 on my first Kaplan practice.</p>
<p>it should be easy i already took calc and stats lol.. just gotta get some formulas in my calc.</p>