Discrete Definition and 829 Threads

There is a question in my text that list an answer in the back of the book that seems wrong to me. It is, "Four microprocessors are randomly selected from a lot of 100 microprocessors among which 10 are defective. Find the probability of obtaining no defective microprocessors." There are...

how many bit strings of length 8 contain either three consecutive 0s or four consecutive 1s?

Prove that for any vectors a and b, |a-b| is less than or equal to |a| + |b| I'm kind of lost, b/c i can't see a case where |a-b| would actually result in a value being less than |a| + |b|. I've tried doing a proof that is similar, and when I was taught, the definition of absolute value...

Discrete Math Help! Here is the problem: Suppose a, b, and c are integers and x, y, and z are nonzero real numbers that satisfy the following equations: \dfrac{xy}{x+y}=a and \dfrac{xz}{x+z}=b and \dfrac{yz}{y+z}=c . Is x rational? If so, express it as a ratio of two integers...

Hello out there, I have a question about the transformation of discrete random variables. I have a joint pdf given by: f(x,y)=\frac{(x-y)^2}{7} where x = 1, 2 and y = 1, 2, 3 I can easily create a table summarizing the joint pdf of RVs X and Y, f(x,y). I now have a transformation...

How do you find the angle between the co-ordinate axis (i.e. the xz plane) and another plane in general?

Find the scalar eq'n of a plane that is perpendicular to the plane with normal vector [3,1,2] and passes through points A(2,-6,-1) and B(1,2,-4). I think that the normal vector can be the direction vector of this new plane. But then, in order to find the scalar eq'n I need a normal vector...

I'm looking for a pretty simple to use discrete Fourier transform utility to use with my asteroid light curves. Does anyone know of a really good program to use. I have found a couple on the internet but they don't specify what format to insert the data so I would appreciate any suggestions or...

Is there such thing as discrete calculus? Or are there general rules to find derivatives and integrals of functions whose domains are restricted to integers or some other discrete values?

Hello (first time poster), i am having quite a bit of trouble with a particular problem on stats (which i despise of!) - in particular, discrete random variables.Ok here is the question: "Find the probability distribution of X in each of the following questions ... Two fair dice...

Hello all, here is a problem I am working on that is giving me some problems. p,q, and N are defined as in RSA i.e. {p,q} in (Z_p,*), N = pq a in (Z_n,*) g in (Z_{N^2}) s.t. g=aN+1 mod N^2 The problem is to show that the discrete log problem base g is easy in Z_{N^2}, i.e. : given...

Hello all, Before I start. You should note: -I'm not just looking for a solution -I've been working on this for hours -I've checked probably about 10 quantum books -I've scoured the internet -My professor can't (or won't) help me (and two other students) so I can't ask around. We three...

Consider the thought experiment involving four hypothetical perfectly equidistantly juxtaposed "co-moving" observers[A,B,C,D], with a flash of light eminating from their equidistant center-point[P]: A_________B _____P C_________D The flash of light obeys what is known as...

Would anyone happen to have some links which briefly explain some of the laws in geometry and/or discrete math? At the moment, i am looking for a summary of the Properties of Circles . Thank you for being as helpful as you always are. -- ps I found MathWorld, although i can not find...

Would anyone have any advice for a Grade 12 student taking the above courses? I have no trouble understanding concepts,yet when it comes to new questions (especially in discrete), i feel lost. Does anyone know of any methods which would fix this problem -- during tests as an example? I do a...

Suppose 2n people sit on a round table and are shaking hands in pairs. Suppose that etiquette is observed and no 2 shakes cross. Let S_n be the number of possible shaking hands arrangements of this sort. Determine S_10.

Suppose 2n people sit on a round table and are shaking hands in pairs. Suppose that etiquette is observed and no 2 shakes cross. Let S_n be the number of possible shaking hands arrangements of this sort. Determine S_10.

Consider the experiment of tossing a die thrice. X is defined as the number of different faces that appear (i.e., X = 1,2,3). What is meant by the "number of different faces that appear"? Could you help me how could I get P(X = 1,2,3)?

Hexadecimal numbers are made using the sixteen digits 0 - 9, A-F. how many hexadecimal numbers are there between the hexadecimal numbers 30 and AF? There are 8 numbers between 3 and A, so I got 3 x 16, but I don't really know.

Five equal negative point charges (-q) are placed symmetrically around a circle of radius R. Calculate the electric field at the center of the circle. My Answer: Each one will be place 72 degrees from the other one (360/5), Each field line is directed toward the center (charges are...

A Discrete Math textbook first proved that the statement: 0 < x < 1 -> x^2 < 1 is true (I have no problem following the proof). It then went to prove the contrapositive: x^2 >= 1 -> x <= 0 or x >= 1 Here's the proof: Assume x^2 >= 1. (no problem here) If x <= 0, we...

Hi, Does there exist a function f: Z+ --> Z which is onto? I had been told there such funciton exists, since both Z+ and Z are countable infinite series. Thus there exists some transformation that could map Z+ to every single Z However, I still can't shake off the idea that since Z+ is...

Can someone give me a definition of discrete mathematics?

Ive been reading different points of view and theories regarding this topic. Wich is, currently, the most reliable one? P.S: Had red a nice one explaining that time, in human perception terms, is discrete, because the brain needs at least the change of the smallest quanto (1 bit?) of...

Hey all, I'm having some problems with this one homework question... We just did The Intersection of Three Planes using The augmented matrix... and here's my question... For what value of k will the following set of planes intersect in a line? x - 2y - z = 0 x + 9y - 5z = 0 kx - y + z = 0

Hello, I am currently taking a course which has exercises/questions whose solutions are based on discrete mathematics. For anyone interested, the link to the course is: http://www.math.uAlberta.ca/~tlewis/222_03f/222_03f.html We are encouraged to discuss these problems with others...

The nature of space and time is discrete (quantum) as shown by Eugene Savov’s theory of interaction [1] in which Zeno’s paradoxes are considered. After assuming discrete space and time, the paradoxes are trivially solved. I cannot understand what’s that fuss about them. The point of these...

It seems that the idea of space being made out of some 1 dimensional fundamental entity is popular these days. Not only does string theory propose the structure of space to be 1D loops, but Loop Quantum Gravity proposes a lattice built of similar 1D loops. What is the advantage of this? I know...

I came across this article: http://www.spacedaily.com/news/cosmology-03i.html Thoughts?