<p>I've heard about Xiggi's rate formula (the [sp1xsp2x2/(sp1+sp2)]) which helped me tremendously on my practice tests.</p>
<p>Does anyone have any strategies/techniques like this that they could share with us?</p>
<p>Thanks!</p>
<p>that formula rarely applies; that kind of prob doesnt occur regularly.
i do have one. personal preference. works only with 1 variable.
make 1 side equals 0, then use TI , to find that variable when it equals to 0.</p>
<p>Logic is the way to go. There's not many of those "shortcuts", and although that one can be very useful for a certain type of question, many others are just a waste of time.</p>
<p>^I agree, don't focus on trying to memorize or even program formulas like that, they are rarely applicable. You really don't need to know many formulas for regular SAT math. But, you should definitely know the given formulas. Here they are:</p>
<p>SAT</a> Given Formulas</p>
<p>Most of the rest of what you should know is factual / conceptual. For a quick review of the most common SAT math formulas and concepts:</p>
<p>SAT</a> Must-Know Formulas</p>
<p>all you need to know is all in the info section at the beginning</p>
<p>^What about basic algebra formulas?</p>
<p>Besides, a little extra knowledge never hurt anyone; it might even turn out beneficial on the SAT.
One example - basic Pythagorean Triples:
[3, 4, 5], [6, 8, 10], [5, 12, 13], [7, 24, 25], [8, 15, 17].
They showed up on the SAT a number of times.
Do you need to know them? No.
Would they save you time and reduce a chance of mistake? You bet.</p>
<p>Maybe you don't need to know all the formulas but they sure do give you confidence when you encounter the problem:</p>
<p>Another formula I can think of is for the "intersection problems"</p>
<p>How many intersections are produced with 10 lines?</p>
<p>it would just be 1+2+3+4+5+6...(n-1)</p>
<p>... which is (n-1)n/2</p>
<p>The more precise wording:
What is the highest possible number of intersections produced by n lines?</p>
<p>I think though it would be better to understand the mechanics of solving this question than memorising the formula.</p>
<p>^ Yea...I forgot the formula mentioned in one of the threads; that's just the way I remember it :) </p>
<p>Sorry.</p>
<p>^ So the formula to figure out the most possible intersection points for n lines is (n-1)n/2 ? </p>
<p>That's actually pretty dam useful.</p>
<p>i am so confused.</p>
<p>(number of lines minus 1)*(number of lines/two)</p>
<p>I think they were going for [(n-1)n]/2</p>
<p>^ Dude, same thing!</p>