<p>These are from the PR 2010-2011 book, I don't understand how to get to the answers! The answer key gives "plug in the answer from the options" by way of explanation and that doesn't help me understand the concept more at all. Is there any way to solve these WITHOUT plugging in? I feel that would be more efficient.</p>
<ol>
<li><p>If sin 30° = cosT, then T could be
(A) -30°
(B) 60°
(C) 90°
(D) 120°
(E) 240°</p></li>
<li><p>If 0° ≤ x ≤ 360° and (sin x)(cos x) < 0, which of the following gives the possible values of x?
(A) 0° ≤ x ≤ 180°
(B) 0° ≤ x ≤ 180° or 270° ≤ x ≤ 360°
(C) 0° < x < 90° or 180° < x < 270°
(D) 90° < x < 180° or 270° < x < 360°
(E) 0° < x < 180° or 270° < x < 360° </p></li>
</ol>
<p>Please help! Thanks.
(Btw the answers are B and D respectively.)</p>
<p>Thanks desafinado, how about the 2nd question?</p>
<p>And here’s a related one i cant figure out either:</p>
<ol>
<li>If tan 45° = tan x, then which of the following could be x?
(A) -45
(B) 135
(C) 225
(D) 315
(E) 360</li>
</ol>
<p>Ans is (C) but how do you get it?</p>
<p>for 2, sin is negative under the x axis and cos is negative to the left of the y axis. so places where only 1 are negative (2nd and 4th quadrants) are going to have a negative product.
for 3, tan = y/x (thats how they teach it in my school) so at 45 degrees y and x are both positive. y/x could also be positive when y and x are both negative, which is the case at 225 degrees in the 3rd quadrant.</p>
<p>you do know that you can use the calculator to find the answer to all of these questions right?..
Sorry if I’m coming off a bit arrogant.</p>
<p>Question, will the SAT Math 2 test cover mostly pre calc topics or Algebra/Geometry subjects? I can’t tell b/c the Barrons’ tests are too hard…</p>
<p>What it seems like from sparknotes/pr is that it’s probably about 40% trig. Most of the algebra geometry is combined as well and will sometimes involve trig manipulation. It’s hard.</p>
<p>Thanks wynter! V helpful.</p>
<p>@ Innercitypressure, do you mean plugging in? If so, yup I can get the answers that way but its slower plus it irritates me as I don’t understand what I’m doing.</p>
<p>@ Desafinado, how accurate do you think sparknotes papers are? Have you tried kaplan’s? Trying to get an idea of which would be a most accurate predictor of scores.</p>
<p>Good luck guys.</p>