Math II - Conic Sections

<p>A lot of the things in Barron's SAT II book seem almost impossible to memorize completely. I've actually got everything memorized up until this point... until I hit Conic Sections!</p>

<p>It's just crazy. There are so many things you need to memorize: eccentrity, b^2-4ac, c, 2a, the equations for different graphs, the vertex, focus, etc.</p>

<p>**I was just wondering do I really have to know all that (about Conic Sections) down pat by memory to get an 800 on Math II ??? (which is my goal) <a href="Btw,%20Im%20taking%20it%20early%20May,%20and%20have%20still%20yet%20to%20just%20read%20through%20the%20book.%20Thus%20the%20urgency%20and%20this%20question">/b</a></p>

<p>Or should I just move on to the next section? Thanks</p>

<p>P.S. Barron's does a poor job of explaining some things: like How are you supposed to know where the vertex and foci of some graphs are?</p>

<p>I would forget about the foci crap and the directrix and eccentricity and hyperbola asymptotes. Here’s what you need to know. You need to understand the standard formulas for circles, ellipses and hyperbolas. Understand how to get them by completing the square. Understand how to find the length of the major and minor axes of an ellipse (and possibly hyperbola). I would forget foci and eccentricity and all that crap though. Just know how to get the equations and understand where they would be on the coordinate plane.</p>

<p>Cool thanks. Are you completely sure though? What did you score ? Thanks</p>

<p>Im glad we did all of this in Pre-Cal. By June I hope Math 2 is cake. =)</p>

<p>btw… How much easier is Math 2 with a TI-89?</p>

<p>Uh, legend, please ask your own questions in your own thread please. thanks</p>

<p>From what I’ve heard a TI-89 doesn’t have any advantages… but again I don’t personally know. Also I believe Latency got a 800 on the test…</p>

<p>ti-89 should help thou. i heard its a lot better than the 84</p>

<p>There usually aren’t more than like 1 or 2 conic section questions.
There was only one when I took it the first time…and I don’t remember any when I retook it.</p>

<p>Just know the basic equations for each conic section (which aren’t hard to memorize…they’re pretty similar) and know how to identify the vertex, foci and whatever by looking at the equations.</p>

<p>I didn’t have a TI-89 when I took it but I think it would have helped a bit. (Only if you know how to work it). It solves algebraic equations for you and all that so you just save some time and avoid careless arithmetic mistakes and whatnot haha like I tend to do. And you really need all the time you can get so that’s probably the main advantage of the TI-89. But you’re totally fine with a TI-84. </p>

<p>Basically, if you have a TI-89 already, take advantage of it. If not, nothing to worry about.</p>

<p>I have one. I need to learn to use it well. I got till June, so I’m hoping I master it by then.</p>

<p>^ It’s not that hard to learn. Just use it from now on instead of your 84 and you should be fine by June! I got it in January and by February, that was the only calculator I felt really comfortable using. Now when I use the 84, it feels kinda weird and I already forgot where some of the buttons are. haha.</p>

<p>I feel so handicapped when I use any calculator that isn’t a TI-89.</p>

<p>Yeah, I got an 800. I believe there was one question about a circle on my test and one question about an ellipse. The circle one was just easy and the ellipse asked me to identify where it crossed Y-axis or something (it was centered at the origin and it was a vertical ellipse. So you would just find the length of the semi-major axis and that would be your Y intercepts – the negative and positive values of it).</p>

<p>smile-vertex and foci coordinates are what I dont know how to get and what Latency said to know worry about…</p>

<p>yeah, you should learn them all, why not, the rewards are much higher than the cost, and yes, the TI-89 has a lot of advantages, i.e. the factor function. But then, aside from the radian to degree measure you have to switch, sometimes, you might need to switch back from approx mode to exact when you don’t need decimal answers and so on. At any rate, it has advantages unless you are too comfortable with your TI-83 to keep it. I got some tutoring and 15 practice tests from a solid boutique tutoring company, [url=<a href=“http://www.e2xmath.com%5DE2X%5B/url”>http://www.e2xmath.com]E2X[/url</a>] , these guys are nerds, but they were awesome, i would recommend them to anyone.</p>

<p>I dont have time to memorize it all. I would if i did. The test is May 5 or something</p>

<p>^ Honestly, it’s not that hard to remember the conic sections. The equations are almost exactly the same. It’s really not that hard and it’s some easy points to get. And believe me, you want to get all the points you can. Especially on the ones that don’t take very long…conic section problems are really fast to do.</p>

<p>Hi -
I’m taking the Maths II SATII in June, and am also having difficulty with conic sections (ellipses, in particular).</p>

<p>How do you find the lengths of the axes from the standard form of an ellipse?</p>

<p>Sorry if it’s a stupid question: I’m an international, and hadn’t studied this at all until a couple of weeks ago.</p>

<p>The number in the denominator. Say its 25, then it’s equal to 5^2. So the length of the axis would be 5 in either direction from the center. </p>

<p>If this number is under the x^2 value, then it will be 5 horizontally right and left from the center. If it is under the Y, then it is up and down.</p>

<p>The major axis (a) is whichever one is longer.
Minor (b) is the shorter.</p>

<p>So the length of the horizontal axis is the (positive) square root of the denominator of the term with the xs in?</p>

<p>Thanks a lot, Shizzle - you’re a lifesaver.</p>

<p>Yeah exactly!</p>