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23h
reviewed Approve Question with the value at risk (VaR) criterion
23h
reviewed Approve Find the points where the function is continuous
2d
reviewed Approve Propositional logic problem: Sales, expenses and happiness of the boss
Jan
25
comment Showing flows converge in the phase plane
Do you really think that I posted my answer before reading the question? -1, which I would gladly change for +1 if you do present a full worked out solution.
Jan
25
answered Fredholm Integral Equations - Sturm-Lioville & Green Function Theory?
Jan
25
comment Showing flows converge in the phase plane
How does it answer the question?
Jan
25
reviewed Approve Why do we put absolute brackets for ln?
Jan
24
comment Moscow State Oral Exam
This may be my translation. The problem is asking about the figure with four edges and with four corners such that all the edges have equal length.
Jan
23
comment Moscow State Oral Exam
The supposed answer is 'No', because it is possible to easily make a quadrangle in 3D space, which is not rombus. But this is, of course, not a standard question. The book I linked (and its file can be easily found in the Internet) has a lot more problems from oral exam, some of which are easy to understand even if you do not know Russian. It starts on page 823.
Jan
23
comment Moscow State Oral Exam
@GridleyQuayle No one said that the figure is flat :) This is one of the "trick" questions.
Jan
23
revised Moscow State Oral Exam
added 198 characters in body
Jan
23
comment Moscow State Oral Exam
@AlexR. An extremely screwed picture, I would, as a witness of actual oral exam, add.
Jan
23
comment Moscow State Oral Exam
@AlexR. You are mixing two different things. Oral exams were not introduced to dismiss unwanted. They were simply used for this purpose. It there were not oral exams, something else was found. For instance, there are no oral exams in US system. But please look up about asian students admission.
Jan
23
comment Moscow State Oral Exam
@AlexR. And what?
Jan
23
answered Moscow State Oral Exam
Jan
23
comment Moscow State Oral Exam
This is a very strange answer, especially given the fact that the oral exams were a normal practice in USSR, and only one or two departments are famous with acceptance/dismissal on the basis of their prejudices.
Jan
23
comment Moscow State Oral Exam
This book has nothing to do with oral exams.
Jan
23
reviewed Reject the relation between positive definite matrix and its ellipsoid
Jan
22
revised Intuition to solving partial differential equations
added 10 characters in body
Jan
21
reviewed Approve Differential Equation $y'+y\cdot\frac{1}{1+t^2}=1-y\cdot\frac{t^3}{1+t^4}$