MathDB

Problems(6)

2013 General Problem 7

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2/4/2013
A fly and an ant are on one corner of a unit cube. They wish to head to the opposite corner of the cube. The fly can fly through the interior of the cube, while the ant has to walk across the faces of the cube. How much shorter is the fly's path if both insects take the shortest path possible?
geometry3D geometryPythagorean Theorem
SMT 2013 Calculus #7

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2/3/2013
The function f(x)f(x) has the property that, for some real positive constant CC, the expression f(n)(x)n+x+C\frac{f^{(n)}(x)}{n+x+C} is independent of nn for all nonnegative integers nn, provided that n+x+C0n+x+C\neq 0. Given that f(0)=1f'(0)=1 and 01f(x)dx=C+(e2)\int_{0}^{1}f(x) \, dx = C+(e-2), determine the value of CC. Note: f(n)(x)f^{(n)}(x) is the nn-th derivative of f(x)f(x), and f(0)(x)f^{(0)}(x) is defined to be f(x)f(x).
calculusfunctionintegrationderivative
2013 SMT Geometry #7

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11/2/2014
ABCDABCD is a square such that ABAB lies on the line y=x+4y=x+4 and points CC and DD lie on the graph of parabola y2=xy^2=x. Compute the sum of all possible areas of ABCDABCD.
geometryconicsparabola
SMT 2013 Algebra #7

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2/3/2013
Find all real xx that satisfy 20x+20x+1333=13\sqrt[3]{20x+\sqrt[3]{20x+13}}=13.
algebrapolynomialquadratics
SMT 2013 Team #7

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2/4/2013
Find all real values of uu such that the curves y=x2+uy=x^2+u and y=xuy=\sqrt{x-u} intersect in exactly one point.
SMT 2013 Advanced Topics #7

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12/31/2016
Robin is playing notes on an 88-key piano. He starts by playing middle C, which is actually the 40th lowest note on the piano (i.e. there are 39 notes lower than middle C). After playing a note, Robin plays with probability 12\tfrac12 the lowest note that is higher than the note he just played, and with probability 12\tfrac12 the highest note that is lower than the note he just played. What is the probability that he plays the highest note on the piano before playing the lowest note?
2013Advanced Topics