<p>If I'm really familiar with everything else on the test, how much of the trig stuff do I have to know in order to do well? I know basic trig stuff like graphs of trig functions, inverses of trig functions, exact values, unit circle, and the law of sines and cosines, but I'm not familiar with the sum and difference, double-angle, or half-angle formulas. </p>
<p>How much will not knowing these kill me on Saturday? Is it something that is valuable enough that I need to memorize it before then? (It is on p.54 section 3.5 of Barron's prep book). I'm using a TI-89 for the test...are there any tricks that can help me solve these sort of problems without memorizing the formulas (I've already tried tExpand and tCollect but they don't always give the same answer...)</p>
<p>There are only 16 so I could do four a day and be finished early next week if I HAD to. Any input? I'm hoping for a 750 or above.</p>
<p>In all honesty, you can program the ones you do not know into the TI-89 (for example, the y= part and press F4 to disable graphing of it). Of course, it is better to know most of them, because of speed, but identities are only a small part of the exam, if they are on it at all. </p>
<p>Generally, I feel it is important to know the Pythagorean identities, sin(a+b) and cos(a+b), and maybe some stuff about cofunctions and whether sin and cos are even or odd. It is easy to think about it in terms of the unit circle. You will probably not need to know sum to product rules, although you may want to store it in your calculator just in case.</p>
<p>It is also important to memorize information about conics, just in case your test has them. They are often easy questions to answer, but difficult to figure out unless you know them off the top of your head.</p>
<p>Don't worry too much. Especially if you have a TI-89, use its functions as much as possible. On my test, I took advantage of the solver and the stdDev() function in the catalog, for instance. It's a huge time saver.</p>
<p>For sure all of the Pythagorean identities and maybe double angle. I don't think power reducing or half-angle will be on there but it couldn't hurt.</p>