May 2008 MATH II

Test Preparation SAT Subject Test Preparation
161

<p>Yeah, one answer was 92...at first i thought it was 77 since it was going up by multiples of 7, but it started at one and not zero.</p>

<p>the circle one the radius remains 5, you just shift it whatever it told you...i forgot what though. pretty easy.</p>

<p>the for the negative absolute value one yah , its the same graph but all
postive values become negative. </p>

<p>i dont remember that question</p>

<p>the last answer was sin2x = 2sinxcosx...divide both sides by cos x and u get a/cosx or a*secx</p>

<p>yeah, midpoint is the same....i hope. </p>

<p>thats what i got for # 6 too</p>

<p>4 years to reach 6 millions</p>

162

<p>does anyone remember the answer to the distance/rate/time problem? It was something like...a 20 km trip, and half of the trip, the person went 40 km per hour, and for the other half, the person went 80 km per hour.</p>

<p>What was the average rate of the trip?</p>

<p>I didn't even attempt the problem, but guessed D (53 1/3) because 60 seemed too easy, but did I get it right???</p>

163

<p>wait no number six should be 2x-y=0 because it was parallel to 2x-y=1?
and yeah, i got 53 1/3 too</p>

164

<p>wait no number six should be 2x-y=0 because it was parallel to 2x-y=1?
and yeah, i got 53 1/3 too</p>

<p>yeah, you're right. maaaan, i forgot to distribute. i suck at life. lol.</p>

165

<p>wat was the answer to the one with C 6 inches away from M plane</p>

166

<p>xlostinwords- I don't remember the answer exactly, but I know you drew a right triangle with 6 inches as one leg, the radius as the other leg, and then the hypotenuse was everything within a certain number. then use the radius of the circle to find the area.</p>

<p>Does anyone know how to explain the last one? was it .9 or .7?</p>

167

<p>I got 108pi=339.3</p>

168

<p>and the last one I got .923; I've explained it before, just look at previous pages.</p>

169

<p>I thought for the last question, the answer was 0.</p>

170

<p>where are you guys getting these scaled scores from???</p>

<p>my pr practice book says i need to get a perfect to get a 800 and a 41 raw is a 690</p>

<p>what do u really think my score is if a omitted 4 and got 5 wrong</p>

171

<p>^ Probably 750 or something like that.</p>

<p>I really wanted to get 800, I think I missed it though.. I have 5 wrongs and 1 blank so far... And there is like 1% chance I get all of the rest right.</p>

<p>I made so many stupid errors.</p>

<p>How is that question (-2, -3)? It's reflecting (3,2) with y=-x, right? I thought it would be (-3,-2).</p>

172

<p>
[quote]
what do u really think my score is if a omitted 4 and got 5 wrong

[/quote]

That's probably around a 760.</p>

173

<p>It's ok sparkling juice i got the same thing.</p>

174

<p>Yeah I thought it was (-3, -2) as well.</p>

175

<p>Transformations</a> in Coordinate Geometry - Reflection in a Line
If you scroll down a little bit, it says that a point (x,y) reflected over y=-x is (-y,-x). Since the original was (3,2), then it would be (-2,-3).</p>

176

<p>ok everyone. chill out. the math curves are usually extremely easy. i skipped 4 on purpose last year, and still got 800 :P Unleashed fury, 4 omit and 5 wrong is probably 750-760ish</p>

177

<p>Another explanation for that reflecting (3,2) across y=-x</p>

<p>remember that (3,2) is a coordinate of (x,y)
When we're reflecting this point across the line y=-x we're saying that the y value is -x and conversely x is -y</p>

<p>(3,2) => (x,y)
When reflected across y=-x
(x,y) => (-y,-x)
therefore
(3,2) => (-2,-3) when reflected across y=-x</p>

<p>For the average running speed question.
I think the question was person x runs 40 km/hr in the first half and 80km/hr in the second half. The total distance is 20km.
First step is to find the total time to run that distance.
First half
d=rt => 10=40t => t=1/4 hr.
d=rt => 10=80t => t=1/8 hr.
T=t1+t2=1/4+1/8=3/8 hr
so the average speed of the entire trip is 20/(3/8) = 53.33 km/hr</p>

178

<p>@goodatlife+fivewinks</p>

<p>The correct answer was the one with 4 uniform bars.
Standard deviation is a measure of how spread out the data is.
If there is only one bar, the other data points are 0. So there is a spread from the mean....meaning there's a standard deviation > 0.
If all the bars are uniform, there's 0 spread from the mean so standard deviation is 0.</p>

179

<p>No; standard deviation is calculated by the following steps: 1) Find mean of data 2) Find difference between each datum and the mean 3) Square all the individual differences 4) Average squares of differences 5) Square root all.</p>

<p>If we had one bar, the set of data would be 80, 80, 80,...80 (example). Therefore, the mean would be 80, the individual differences would be 0, do everything else to it, and you'd still get 0.</p>

180

<p>yes, the standard deviation one was A, the one with one big bar.</p>