<p>What's the easiest way of finding an intersection between to functions? (say, for example y = lnx and y = x - 2?)
I know I can do it by graphing, but that takes forever.</p>
<p>Also, what's the "solver function" that's supposedly on the calculator?</p>
<p>Are there any other calculator tricks that I should know about before taking the AP Calc BC exam?</p>
<p>I’d like to know this too, hah.
For a TI-84, that is.</p>
<p>I am also taking the AP Calculus BC test this year. I think you may be talking about f2 solve. It is under the algebra menu. Type in the equation, then a comma, then the variable you are solving for.
Do you know how to do integrals, derivatives, and sums on your calculator? They are under the calculus menu on the TI-89 (f3). Most of our tests in BC are noncalculator, but I have learned this from doing in class problems. There are a lot of tricks on the TI-89. I have had this calculator since pre-calc last year and I still probably only know less than half of its capabilities. Most of the programs on the TI-89 are unnecessary for the BC test, but knowing the basics does save you time. However, as you probably know, you have to be careful to put all of the punctuation in correctly or you will not get an answer.
Good luck!</p>
<p>I don’t use the Solver feature on the TI-84 much at all, so I’ll let someone more familiar with it explain its mechanics. I know it’s under [MATH] [0] on the TI-83/84 model.</p>
<p>As far as the intersection of two graphs, so long as the intersection point is shown on the screen, go to the [CALC] menu (using [2nd] + [TRACE]) and select option [5] intersect. It will ask you to press [ENTER] when you’re on your first curve, [ENTER] again when you’re on your second curve (use the up and down arrows to toggle between curves), and then [ENTER] on a “guess”. If there’s only one intersection point, all the guess will do is speed up the process by a little bit. If there’s more than one, though, picking a point closer to the intersection point in question will likely cause the program to lead you to the intersection point you’re looking for. You also don’t have to scroll to make a guess, you can type in a numerical value for the guess.</p>
<p>And have fun with the 2006 test. :)</p>
<p>Poeme – unfortunately I have a TI-84, so I can’t do integrals or derivatives on my calculator :(</p>
<p>TheMathProf – how do I type in a numerical value for the guess? Whenever I press a number button, the graph screen disappears…</p>
<p>Thanks everyone!</p>
<p>The 2006 test was fun up until the last two problems…</p>
<p>For the guesses just press enter again; not like it matters. If you need two points, press left/right until you’re closer to 1 point than the other, and then hit enter.</p>
<p>You can arrow scroll to guess, also, but I suspect you probably pressed enter too many times if the graph screen disappears, and it’s already found the intersection.</p>
<p>I usually use the arrow to guess, but I find that it takes too long. </p>
<p>I tried pressing just a single number as a guess after doing CALC - 5: intersect, but that takes me away from the graphing screen.</p>
<p>Ah, you have to hit [ENTER] twice: one on each curve first (when it asks “First curve?” and “Second curve?”) and then you can type your guess after that.</p>
<p>You cannot get the TI-83/84 to display a derivative or integral function, but you can get it to graph a derivative or calculate a definite integral. I find this to be particularly helpful. (They’re found under [2nd][TRACE] and [2nd]<a href=“8%20or%209”>MATH</a>).</p>
<p>Er, I’m pretty sure that the Ti-83/84 can solve derivatives and integrals. nDeriv and nInt, respectively. Just know which parameters go where.</p>
<p>The solver function is in “Numeric Solver.” You enter the equation, enter a number, and press 2nd > enter (or equals, I forget). It solves for the answer closest to the number you gave.</p>
<p>The 89 is certainly more user friendly. But that’s as far as it goes in terms of differences when talking about math up to low-level calc.</p>
<p>I have a TI-84.</p>
<p>If I want to find the point of intersection between y=lnx and y=x-2, I:</p>
<ol>
<li> Go to apps and turn on Inequalz (I always have this turned on)</li>
<li> Type in my equations into Y1 and Y2</li>
<li> Hit [GRAPH]</li>
<li> Hit [ALPHA] and then the [ZOOM] or [TRACE] button (it will say “PoI-Trace” on the screen)</li>
<li> The calculator will give you the intersection of the two lines</li>
</ol>
<p>This is also how you can graph inequalities (you’ll see the options on the [Y=] screen, use the alpha button when the = sign is highlighted to choose the inequality sign). Very, very useful. Also, if you type an equation into Y1 and a 0 into Y2, use the PoI-Trace button to find the x-intercepts.</p>
<p>thank you all so much! this has been incredibly helpful!</p>
<p>aeroengineer – do you recommend getting the 89 for college? (i’ll probably be taking calc II or whatever the class is that comes after BC. they call it math 114/115 at penn. but i think that’ll be the last class of my math career)</p>
<p>also, more questions about BC calc in general</p>
<p>-do the MCs and FRs get progressively harder (1st question easiest, 3rd question hardest, 4th easiest, 6th hardest, etc.)
-what’s a solid 5?
-i have the PR book and my stewart textbook. should i get anything else to help me study?</p>
<p>I’d actually contact somebody at Penn (or whatever college you end up going to) about the TI-89. Some colleges require the TI-89 and some colleges prohibit it for tests and such. If the college isn’t going to openly allow you to use it, I don’t think it’s worth the investment for one class to go and learn it on your own.</p>
<p>I don’t think that the questions get progressively harder as they go, although I’ve noticed that the first question in the MC tends to be a little light, and sometimes the last question can be a little time-intensive. There are some very easy questions towards the end of the MC, and some challenging questions earlier on in the MC.</p>
<p>I’ve usually found question #6 to be one of the more manageable FR questions on the test, at least in my experience. (That’s speaking more to the AB test than the BC test, admittedly.)</p>
<p>I’m not familiar with the BC cut scores or the prep books, so I’ll allow someone else to speak to those.</p>
<p>wait… I’m soo lost… </p>
<p>are we allowed to use the calculator to find the intersection of 2 functions on the AP exam?? </p>
<p>I know we’re allowed to:</p>
<p>Plot the graph of a function within an arbitrary viewing window
Find the zeros of functions (solve equations numerically)
Numerically calculate the derivative of a function
Numerically calculate the value of a definite integral </p>
<p>So does that count as finding the zeros?? And is there anything else we’re allowed use the calculator without showing the work?</p>
<p>Yes, finding the intersection counts as finding the zeroes, because finding where f(x) = g(x) is equivalent to finding where f(x) - g(x) = 0.</p>
<p>And that list you have is it.</p>