***June 2010 Math I Thread***

<p>I got 8 pi. Also got 6.14 for diagonal and 20% for shirts</p>

<p>pclariz- agree 6.14 for diagonal, disagree with 20%. it had to get to 15, and the other was 10. so you would be right if the sales were equal, but b had 2x as many sales as a, so it was 17.5.</p>

<p>I took Math I…lol. I think I skipped 1 out of the first 30, but skipped 6 out of the last 20 and went back and guessed. I’m predicting a 680 for me on that.</p>

<p>What was te cylinder and concentric circles answers?</p>

<p>what was the f^-1(f^1(x)) for all real #s? i put -x</p>

<p>and what was g(x)=f(x+2) or something?</p>

<p>I got x for the inverse one and yes f(x+2) was an answer I think. What was the answer to the last one with the cone thing?</p>

<p>got 8pi for the circle one and 1/9 for the cylinder…what was the coordinate one (8,5) , 9,5 or 10,5</p>

<p>I got 25pi for the circle and I dont remember a cylinder</p>

<p>no i think the cylinder one was 6. that was the one with 75 percent filled, right?
and the fraction log one was 9 right?</p>

<p>**The cone<a href=“last%20problem”>/b</a> = 1/26</p>

<p>The concentric circles one = 16pi (here’s why: you can make an isosceles triangle with 2 radii coming from the big circle, and then draw a perpendicular bisector from the center of the small circle to the tangent (aka the radius of the small circle. Let the radius of the big circle be R and let the radius of the small circle be r. What we’re looking for is (R^2 - r^2)pi. We know that each half of the tangent is 4 (8, bisected by r). R is the hypotenuse of the triangle that has 4 and r as legs. Thus R^2 - r^2 = 4^2
SO… if R^2 - r^2 = 16, then (R^2-r^2)pi = 16pi.</p>

<p>The **inverse function one ** was x. f(f^-1(x)) = x. This is not a negative exponent; it is an inverse function.</p>

<p>The profit percentage one was indeed 17.5. This is because shirt A only accounted for only 1/3 of the company’s income. SO…(1/3)<em>.1 + (2/3)x = .15
Since (.15-(1/3)</em>.1) divided by (2/3) = .175, the answer is 17.5 percent.</p>

<p>Sorry, I can’t remember the parallel lines one, but I do remember it was one of the two you listed (either c=g or a=e), but one of the two pairs (I can’t remember which) was bounded by different lines (as in, you had to think about as if the only lines existing were the top and bottom two plus the diagonal. Since, if those 3 were the only lines, one of those two pairs would not exist, it can’t be the correct answer.</p>

<p>The horizontal shift one was f(x+2), because you’re moving it to the left, it’s +2 not minus, and because it’s horizontal the +2 goes inside of the parentheses (if it was a negative vertical shift, it would have been outside and been negative, i.e. f(x) - 2.</p>

<p>no the last question cone one is what i meant.</p>

<p>i took math 1 & 2 this morning. I should of taken math 1 first because 2 destroyed me. Anyways, i glanced at some of the answers and they seemed to match with mine. I started off really well, but once i got to 35+ the difficulty increased and i guessed and left some blank.</p>

<p>Why was it 1/26??? I put 1/27</p>

<p>cos =rad15/4</p>

<p>Tan of something was answer also and the log was def 9</p>

<p>I put (10,5) for the coordinates (was kinda a guess though) anyone else get that?</p>

<p>Also did anyone get $325 for that one with the variable cost and fixed cost? I didnt really understand it.</p>

<p>i put (9,5) for the coordinates did anyone else get that?</p>

<p>Okay this is how you do the variable one, I forgot the choices though. </p>

<p>Okay they said for 4000 people, the total cost is $1300. </p>

<p>For 2700 people, the cost is $970. </p>

<p>Now you subtract these numbers and you get for 1300 people, it is $330. Note the fixed cost gets canceled in the process and this is why you can use this. Now reduce and you get for 130 people, it is 33$, this is the variable cost.<br>
Now to determine the fixed cost you divide either 4000 or 2700 by 130 and then multiply by $33. You get respectively, $1015.38 and $685.38, this is rounded so it may not be as accurate.<br>
Now subtract $1300 by $1015.38 and you get $284.62 and this is the fixed cost. You could also subtract $970 by 685.38 as a way of checking for the other one and sure enough you get $284.62.</p>

<p>So the fixed cost is $284.62 and the variable cost is for every 130 people you add is $33.</p>

<p>So now to determine how much this will cost for 1000 people, this will be 1000 divided by 130 and then the quotient multiplied by 33 and you get $253.85 for the variable cost and the fixed cost is $284.62. Now just add these two and you get $538.47 and this should be an answer choice.</p>

<p>On the test I blanked out on this one and then figured it out at home…fail!!!</p>