<p>Could someone explain or clarify how to do some of these:
- Parametric equations
- Domain/range inequalities
- Functions like f(x), -f(x), f(-x), -f(-x) (i dont know what those mean)
- Matrices (determinant, multiplying)
- Function crossing over axises questions
- Descartes rule of signs</p>
<p>And add any shortcuts you may find useful to chip off some time. Thanks in advance :)</p>
<p>i suggest going to SparkNotes:</a> SAT Subject Test: Math Level 2: SparkNotes: SAT Subject Test: Math Level 2 for anything/everything</p>
<p>otherwise:</p>
<p>range/domain inequalities
this is a way to say what a functions domain and range are</p>
<p>domain: tells you which values of x for which the function is defined
for example y = sq root of (x-4)</p>
<p>sq root can't be taken of a negative, only zero and positive vals
therefore, x can be zero or greater
w/ inequalities its written as: x >(or equal to) 0</p>
<p>same thing goes for range</p>
<p>Matrices are really easy to do with a calculator! so learn how.
Parametric are just two equations pretty much in my opinion
Set mode to PAR and enter the equations..
f(x) = function of x.. x is the input or f(x) is the Y pretty much
- f(x) = -y
f(-x) means you are inputing a value after you have negated that value
-f(-x) = negate the final value after inputing a negated value into the equation.
Descartes rule of signs?? isn't that where the Quadrants and either x is pos or y is pos..etc?
functions crossing over axes? idk what you mean.</p>
<p>Descartes Rule of Signs is just about useless but I can explain it anyway.
You have a function, say f(x) = x^3 + 5x^2 -3x +2
Now you see how many sign changes (positive to negative) there are (so 5x^2 to -3x is a sign change as is -3x to 2). You have two sign changes, so there are either 2 positive roots or 0 positive roots (subtract by two)</p>
<p>Now you evaluate f(-x) which ends up being -x^3 + 5x^2 + 3x + 2
Again see how many sign changes there are (only one this time). This means you have 1 negative root (can't subtract by two because there's only one)</p>
<p>Hope that helped. I'm bad at explaining without a piece of paper =p</p>
<p>easier way for that: plug it into the calculator.
lol
:]</p>
<p>^ IlDesi I dont really get it lol...why do you subtract 2 from first one?</p>
<p>It's just part of the rule. If you ended up having 6 sign changes, you could have 6, 4, 2 or 0.</p>
<p>But it really is entirely useless.</p>
<p>I guess it is just a rule, suppose you get 4 sign switches, then it would be either 4,2, or 0.</p>
<p>edit: person above beat me :P.</p>