The original version of this problem made the situation even worse: it merely asked for some correct angle, so you could also find another correct angle and again get no credit. There were still other difficulties. The notation for inverse trigonometric functions is not standardized. Some books use arcsin, some sin -1 , some Sin In some places Sin -1 stands for the inverse function that is, the range of sin is restricted so that it has an inverse , and sin -1 stands for the inverse relation that is, sin -1 5 is the set of all angles whose sin is 5.
Finally, even if you understood sin -1 to be a function, it might be unreasonable to expect you to remember its range, or the range might not be standardized in all books.
In writing this problem, we assumed that sin -1 is a function with range [- 5 51 cos -1 is a function with range [ 0 ,ir], An equal-arm balance used in a school chemistry lab is defective. A student attempts to measure grams of a certain chemical by placing calibrated weights totaling grams in pan A and balances the weights with Wi grams of the chemical in pan B. He then places the calibrated weights totaling grams in pan B and balances the weights with Wj grams of the chemical in pan A. Mathematically, this is a very nice problem about the idea of compensating for error through symmetrization.
However, the problem has two difficulties. First, many students may have 48 Contest Problem Book V no familiarity with such old-fashioned mechanical balance scales.
Let r be a random number strictly between 0 and 1. Then which expression below gives an integer from 0 to 10, inclusive, with each integer equally likely? A circle of radius r goes through two neighboring vertices of a square and is tangent to the side of the square opposite these vertices. This problem, proposed for the exam, was an attempt to get some ideas about sampling accuracy onto the AHSME, in an continuing effort to indicate that statistical ideas are important.
However, there was already another coin toss problem under consideration and the committee preferred it.
We worried that this problem introduced too many ideas that would be new to most participants and that therefore it might not provide an accurate measure of ability. Answers are given in percents. For instance, 0.
Boldface indicates the correct answer, so E was the correct answer to problem 1 in From these tables readers can get an idea of how hard other very good students found these problems. If you picked one of these incorrect answers, analyze carefully where you went wrong. But for problem 26, the B The points in question are the points of intersection of the original circle C and the circle of radius 3 cm around P. Two distinct circles intersect in at most 2 points.
A Not both p and q are odd, since then r would be an even prime greater than 2, which is impossible. Thus one of p and q is 2. There are now 4 equilateral triangles with side length 1. Thus tanf? The degree is defined to be n, the highest power of x. B Let x be the list price in dollars.
The market analysis objective was to gather market information and create a comprehensive strategic outline that analyzes the Texas wine market. The reason it makes you warmer is that the human body has an internal source of heat. Find the area of A ABC. Roger D. B Draw in the perpendicular bisector of chord EF, as shown in the adjoining figure. Students completed a survey regarding the near work demands they experienced during the Winter break and the teaching semesters. Yes, the output of the difference amplifier is inverted; more positive when there is too little of something and more negative when there is too much of something.
D Let w be the number of women, m the number of men. Thus the average age for all is. Except for the leftmost expression in the previous line, the computation of the average is the same computation one would do if there were exactly 11 women and 10 men. For this problem, that approach leads to answer C. But averages can be weighted, as in this problem, and so C is wrong. E Consider the first few powers of 3, 7 and 3 7 13 9 49 27 Let u n be the units digit of n.
This solution can be expressed much more briefly using congruences.
C A total of 6 can be achieved by 7 equally likely ordered triples of draws: 1,2,3 , 1,3,2 , 2,1,3 , 2,3,1 , 3,1,2 , 3,2,1 , 2,2,2. D Look at the first digits, letting z denote the rd digit. Dividing by 3 we get with remainder 0. Thus C consists of the first 3-digit integers. Since the first 3-digit integer is not or , the th 3-digit integer is Thus the only possibility is point C.
Applying this to the point F, its reciprocal must be in quadrant IV, inside the unit circle. The only possibility is point C. Actually, since x is real, to as defined can only take on values equal to or greater than 1.
First. Five. Years. A compilation of team tests from. The Mandelbrot Competition, Sam Vandervelde. Page 3. Copyright © Greater Testing. The first five years.. a compilation of team tests from the Mandelbrot competition, Home · The first five years.. a compilation of team tests from the.
This problem can be done almost as quickly, and with much less thought, using a calculator. This problem could be changed to make ordinary calculators useless by making the distractors smaller than the roundoff errors of these machines. However, the problem then becomes ungainly.
Thus 5 is the unit circle without boundary and the area is 7r. A We claim that the ratio of consecutive radii is constant, that is, the sequence of ra dii for m a geometric progression. The claim should be intuitive — the picture for any two consecutive circles looks the same except for a change of scale — but here is a proof. In the figure below, three consecutive circles are shown.
Their centers P, Q and R are collinear, on the line bisecting the angle formed by the two tangents. E We will show that the ratio of perimeter to area in a triangle can be changed at will by replacing the triangle by a similar one. Thus in each class of similar right triangles, there is one with perimeter in whatever length units, say cm equal to area in whatever area units , that is, with the ratio being 1.
Alternative solution sketch.
postdollarworld.com/keriz-spy-on.php This is one equation in two nonnegative real variables. Therefore, one should already believe that E is correct. A complete analysis subtle, but left to the reader! D Let P E be the probability that event E occurs. Many people assume that if event A has probability p and event B hs probability q, then the probability of both A and B is pq; that is, they assume that events are automatically independent.
This problem was devised to make students confront such beliefs, and to make them see just how dependent different events can be.
E We first construct the figure shown, which results from bisecting the sphere-shadow configuration with a vertical plane. C Draw in line DE. Since these two triangles have a common base DE, the altitudes on this base must be equal. So much is undetermined in this problem - the shape of the triangle and the positions of E and F on their sides - that one might well think that there are many configurations in which ABE and DBEF have the same area and so E should be correct.
There are indeed many different configurations. However, the area is uniquely determined.
C Let the square be placed in the coordinate plane as in the first figure: D is placed at the origin so that algebraic expressions for the distance from it will be easy to interpret. Alternative Solution. C The number n must be a product of two or more primes greater than 10, not necessarily distinct.
B Draw in the perpendicular bisector of chord EF, as shown in the adjoining figure.