CB BB Math 2 Solutions

<p>Hey guys,</p>

<p>I'm reviewing for the Math 2 subject test on January 27th, and I think the best way for me to study is to learn every singe question inside-out from the College Board Official Study Guide. So with that in mind, I worked through every problem, and typed up the solutions for every question (except#49) here to share with CC!</p>

<p>I didn't copy the solutions in the back of the book. The way I typed up the solution and the method I used is how I worked out the problem and thought through it. Obviously the ones I omitted and got wrong when I actually took the timed test I didn't know exactly how to do, so the ideas are similar to the ones in the back of the BB. And some are just the same because thats how I worked through it. Anyways, hope it helps some other people who are also studying for the math 2 test! 800, here I come!</p>

<p>Keep in mind these MAY NOT be the best way or the quickest way to work through each problem. Its just what I think is easiest, or at least how I got to the answer.</p>

<p>Good luck to everyone taking math 2 in January!</p>

<p>Part I (1-25):</p>

<ol>
<li><p>D: x is any number. Plug in any real number, say 1 (for simplicity). Simplifies to 9=3k/4, 36=3k, therefore, k=12.</p></li>
<li><p>C: It asks for the relationship b/t K and F. K=C+273, and since C=5/9(F-32), K=5/9(F-32)+273. Just plug in the value of C in terms of F into the K equation.</p></li>
<li><p>D: (5-11)/(-2-3)=-6/-5= 1.2</p></li>
<li><p>A: y+z=5, x+y+z=10, so x+5=10, therefore x=5. x+y=2, 5+y=2 y=-3</p></li>
<li><p>C: g(5)= e^5, f(x)=3ln(e^5)-1=14</p></li>
<li><p>E: If a plane intersects the cube perpendicularly, then the intersection is a square. A square by definition is a parallelogram. I and II are true. Intersecting the plane at any corner diagonally will produce a triangle. III is true.</p></li>
<li><p>C: The rocket goes up vertically, so it creates two right triangles. The ninety degree angle is obviously between A and B. tan84.1(12/x), x gives length of bottom left of triangle. tan(62.7)=12/x, x gives lower left of triangle. Add these two lengths together for lengh of 7.43km.</p></li>
<li><p>D: x^2=15^2-12^2=225-144=81</p></li>
<li><p>D: distance b/t origin and P is sqr.(x^2+y^2)=d distance b/t origina and P?= is 2sqr.(x^2+y^2), which is 2d, by means of distance formula and then simplification (factor out 4).</p></li>
<li><p>B: you know what f(x) equals, so plugging in some value of x into f(x) would equal f(g(x)). Plugging sqr.(x^2+1) into f(x) gives f(g(x)).</p></li>
<li><p>E: take inverse sinA=.8 to get A=.927295 Plug this value into cos(90-A), plug this into your calculator, and you get .8 You can also notice that cos and sin are complimentary functions, so complimentary angles equal the same thing in sin and cos functions.</p></li>
<li><p>C: (x,y,z) must be a 3-dimensional shape. x^2+y^2+z^2=1 must be a sphere, which is the only choice that is 3-D.</p></li>
<li><p>B: Graph the function in your calculator. A vertical asymptote occurs at x=4.</p></li>
<li><p>D: c is a constant, so it must be the y-intercept, or the shifter of the graph along the x-axis. The y-int looks to be around -80, and the only answer choice around that value is -72.</p></li>
<li><p>A: 1/cos(x)=sec(x)=1/.4697=2.1290 OR take inverse cos of .4697 to get x, and plug x value into sec(x).</p></li>
<li><p>B $7 per person, plus $200/n for bus ($200 of bus divided by n amount of people going), plus $14/n ($14 for two chaperones). 7+200/n+14/n. 7n/n+200/n+14/n= (214+7n)/n</p></li>
<li><p>B: The points are two points on the x-axis. y=2 is a line right in between the two points which is always equidistant. All the others aren?t equidistant from the two points, therefore y=2 is the only plausible and correct answer choice.</p></li>
<li><p>A: first term divided by (1-rate) give infinite sum, so 1/4/(1-1/2)=1/2</p></li>
<li><p>D: subtract p to each side, and then add s to each side, resulting in 2s>0. Divide each side by 2, giving you s>0.</p></li>
<li><p>D: A isn?t true because it is obvious a or b can be any number, not just 0. B is not true because when the function is decreasing, b>a. C is not true because when the function is increasing, b>a. E is not true, because it would contradict the fact that f is a function. By POE, D is the only answer choice left. Since all the other answers aren?t true, and f is a function, and f(b) and f(a) takes on different values, it must be true that a does not equal b.</p></li>
<li><p>C:.75 of a population lived w/in 10 miles of the city, and out of those .75, .40 lived in single family homes. These two are dependent events, so you have a .75 chance of choosing somebody living w/in 10 miles of the, and then out of the .75 chance, you have .40 chance of them living in a single-family home. So .75 chance multiplied by .40 chance equals.3 chance.</p></li>
<li><p>C: sketch a figure. The smallest angle is opposite the smallest side, which is 3. Set up a trigonometric equation. tan(x)=3/4 Take inverse tan to get x=36.86989765, which rounds up to 37.</p></li>
<li><p>C: A line is perpendicular that has a slope that is a negative reciprocal of the original line. So in this case, the perpendicular line would have a slope of ?, which is seen in choice C.</p></li>
<li><p>B: Graph in calculator to notice the range (y values) is B.</p></li>
<li><p>E: 8,8,8 has a standard deviation of 0 because they are all equal numbers with no difference or deviation in value.</p></li>
</ol>

<p>Part II (26-50):</p>

<ol>
<li><p>D: 1000 is the initial amount, so P=1000. A is the final amount, so A=5000. Plug into the equation: 5000=1000e^.08t Solve to get t=20.1</p></li>
<li><p>B: If sin(x)>0, then x must be in quadrants I or II, where sin (y) is positive. If sinx is positive, then cosx must be negative in order to satisfy the inequality. cos (x) is negative only in quadrants II and II, so x can only be in quadrant II to satisfy all conditions.</p></li>
<li><p>C: For every x and ?x in the function, there is an equal f(x) for both values. This means that 3 and -3 creates the same value. f(3)=f(-3) f(3)=8, so f(-3)=8, and so (-3,8)</p></li>
<li><p>E: If x^2=y^2, then x can be equal to y, but x and y can also be negatives of each other. For instance 25=25. x can be 5 or -5, and same for y. E is not true. </p></li>
<li><p>D: 9 possible students in first position, 8 in next, 7, then 6, etc. This is 9!, which is 362880.</p></li>
<li><p>Graph and use table function, starting at 1 and going by small intervals of say .1. You can see that from either side, the function approaches 1 as x approaches one, though it is undefined at x=1.</p></li>
<li><p>C: f(2)=1. Graph f(x), and trace all the values until one of them equals 1. f(4/3) gives 1.</p></li>
<li><p>Graph this, with window ranges of x in the answer choice. I used this method to get the answer while taking the test, but it took forever. But the back of the book says something like this: the period of y is the same as the period of tan(3(pi)x), since only the coefficient inside the trig affects the period. The period of tan(x) is pi, and the coefficient of x in y is 3pi, making the period shrink. Since its 3pi coefficient, then multiply 1/3pi by pi, which give 1/3. </p></li>
<li><p>C: Draw a right triangle. The hypotenuse is 50, and the East Road is 20 miles. Use the Pythagorean Theorem to find the North Road, which is equal to 45.83. Add up the north and east roads, which is 65.83. Distance divided by velocity gives time, which is 1.46 hours. .46 hours is 27.6 minutes, so it takes about 1 hour and 28 minutes.</p></li>
<li><p>C: f(x) equals 0 at -1 and 2, so -1 and 2 must be zeros of the function f(x). (x+1) and (x-2) is in f(x). Only choice C has those factors.</p></li>
<li><p>D: A factor of a number must be a multiple of its prime numbers. You can get 10 by 5<em>2. You can get 20 by 2</em>2*5, etc. You cannot get 30 by any multiplication of the prime factors, so 30 cannot be a factor of n.</p></li>
<li><p>E: Graph sin(x) and 3cos(x) in a viewing window of [0,pi/2]. Their intersection gives x. You can also rewrite the equation to tan(x)=3 by dividing cos(x), and then solving for x.</p></li>
<li><p>To find f(x) inverse, switch y and x, and solve for y. f(x) inverse=x^2/50. Plug 10 into this inverse function. f(10)=10^2/50= 2</p></li>
<li><p>C: Defined as the previous two terms added together, so 1,1,2,3,5,8,13,21,34,55?10th term is 55.</p></li>
<li><p>D: Graph the function. It is increasing for x equal to or greater than 3. The function crosses the x-axis at 3 points, so it must have 3 real answers. I is true. It cannot have 2 more nonreal answers since there are already 3 answers to this third power polynomial. II is not true. f(x) is greater than -16 for all xgreater to or equal to zero, since -16 is a local minimum. III is true.</p></li>
<li><p>A: fg(0) has to be 0 since f(0)g(0) is 0. The whole function has to be negative, since f is negative on the left, and g is negative on the right. The only graph that fits all of these conditions is A.</p></li>
<li><p>B: graph both of the functions. The graph continually intersects only at negative numbers and 0. Another method is to see that the x must be negative, because that would make the right side positive. A square root of a number must be positive, and the value inside must positive, and negative squared makes a positive under the radical. Only negative and zero of x works, so B is the answer.</p></li>
<li><p>C: Use law of sine. sin(30)/3=sina(a)/4, 4sin(30)=3sin(a), sin(a)=4sin(30)/3, take inverse sin, a=41.81, sin(41.81)=2/3</p></li>
<li><p>A: The longest segment is the line between two opposite corner vertices. To find this segment length, use the ?Super Pythagorean Theorem?. 8^2+4^2+1^2=length^2 length=sqr.(80), which simplifies to 4sqr.(5)</p></li>
<li><p>A: I don?t know how to get the base into MWord, so just assume the base of a is there! Anyways, log45=log9*5=log9+log5=log3^2+log5=2log3+log5. Since log3=x and log5=y, 2log3+log5=2x=y</p></li>
<li><p>B: Pick any random number for 0<x<pi/2, say pi/3. sin(pi/3)=.86603=t. tan(pi/3)=1.73205 Plug in t=.86603 into each equation to find which one equals to tan(x)=tan(.86603)=1.73205. Only choice B works out.</p></li>
<li><p>E: Graph y=x^2-2x+k, using k as ?a constant greater than 2?, say 4. When you graph this, notice the graph of x^2 shifted to the right 1 unit. You can eliminate choices A, B, and D. The graph shifted 3 units up, which is one less than k where k=4. That means it shifted k-1 up. Right 1 unit and up k-1 units, which is answer choice E.</p></li>
<li><p>A: v=1/3(pi)r^2h This is the volume of a cylinder. .85v=1/3(pi)(kr)^2.92 this is the volume after making the changes, .85(1/3(pi)r^r(h))=1/3(pi)k^2r^2.92 replace v and simplify. Solve for k, which is .96. If you multiply r by .96, you are reducing it by 4%. </p></li>
<li><p>Never learned matrixes, so I won?t even touch this problem!</p></li>
<li><p>A: w is (-a, bi) ?iw=-i(-a, bi)=(ai, -bi^2)=(ai, -b
-1)=(ai, b). This means that b is now the real number, and a is the imaginary number. Both are positive, so ?iw must be in the first quadrant. Only A is in the first quadrant.</p></li>
</ol>

<p>wow...thanks?!</p>

<p>NP. All I hope is that it helps someone in their study!</p>