What is Pdf: Definition and 345 Discussions

Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1993 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. Based on the PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, vector graphics, raster images and other information needed to display it.
PDF was standardized as ISO 32000 in 2008. The last edition as ISO 32000-2:2020 was published in December 2020.
PDF files may contain a variety of content besides flat text and graphics including logical structuring elements, interactive elements such as annotations and form-fields, layers, rich media (including video content), and three-dimensional objects using U3D or PRC, and various other data formats. The PDF specification also provides for encryption and digital signatures, file attachments, and metadata to enable workflows requiring these features.

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  1. D

    Converting PDF formats to MS word 2010?

    Hi,guys. I'm doing my paper with my teacher now,we are trying to convert 1500's of pdf files to word 2010 that has not been labeled correctly so using the built in feature that acrobat has does not allow the tables and colums to convert without going all over the place. Is there anyway to do...
  2. E

    Matrix notation - Two jointly Gaussian vectors pdf

    Hello I am having trouble deriving using block matrix notation the conditional pdf of two joint Gaussian vectors: I assume that it just involves some re-arranging of eq 1 (attatched) but am unsure if taking the inverse of the resultant matrix in eq 1 is valid and if the order of...
  3. E

    Gaussian random variable joint density with discrete pdf

    Hi all, I am having trouble with the concept of joint pdf's. For example - a set Z1,Z2,...ZN are each gaussian rv. Let Z1~N(0,1), let X be +1 or -1 each with probability 0.5. Z2=Z1X1, so Z2 is ~N(0,1). (I assume this to be As Z2 is just Z1 multiplied by a simple factor, an instance...
  4. Simfish

    Is there a way to easily rename an academic pdf to author names+year+title?

    I did try using Zotero (as suggested from http://www.quora.com/Is-there-a-way-to-easily-rename-an-academic-pdf-to-author-names+year+title), but it wasn't able to find names for half of my PDF files.
  5. Rasalhague

    Pdf and pmf as random variables?

    If the set of real numbers is considered as a sample space with the Borel sigma algebra for its events, and also as an observation space with the same sigma algebra, is a pdf or pmf a kind of random variable? That is, are they measurable functions?
  6. E

    Guassian pdf is sum of two other RV Integral evaluation -

    Could someone please advise me how to put the integral from + to - infinity notation used $ exp{-1/2(y-x)^2(A^-1) + x^2(B)^-1}dx Into the form k1 $ exp[-k2(x-k3)^2]dx using the fact that $exp(-1/2x^2)dx = 2pi^1/2 I have encountered this problem when trying to derive the conditional...
  7. S

    The PDF of the exponential of a Gaussian random variable

    What is the PDF of the exponential of a Gaussian random variable? i.e. suppose W is a random variable drawn from a Gaussian distribution, then what is the random distribution of exp(W)? Thank you!
  8. C

    Convert PDF Equations to Word Doc

    Does anyone know of any software that can convert a PDF with complex equations to Word? Word uses cambriamath and products like adobe are not equipped to convert from PDF to Word. The issue is this - we need to update many equations and charts which are currently in a PDF format. We need...
  9. Q

    What Are the Limits of Integration for Obtaining the PDF of V = (X^2)/Y?

    Homework Statement Given: The joint probability distribution function of X and Y: f(x,y) = 2xe^(-y), x > 0, y > x^2 0, otherwise Obtain the pdf of V = (X^2)/Y The Attempt at a Solution The interval of V is (0,1) because Y is always...
  10. A

    Probability Distribution of Random Variable X from a Double Dice Roll Experiment

    The question is "An experiment in which a dice is tossed twice. Let X be the random variable defined by recording the higher of the 2 values obtained in the experiment. Determine the probability distribution of X." I know that the range of this distribution is {1,2,3,4,5,6}. For P(X=1) both...
  11. S

    PDF highest density interval sketches

    1. Sketch a probability density function for which the highest density interval (HDI) takes the form: (i) (a, b) (ii) (a, b) U (c, d) (iii) (a, b) U (c, d) U (e, f). where a < b < c < d < e < f. 3. Now i believe that the graphs are going to look something like like e^{-x^2}...
  12. T

    Checking Convergence of PDF Integral

    Dear all, I have a PDF in independent variables q, \mu and h, all depending on x and y. I wish to check whether or not this PDF converges, which means checking that the normalisation constant converges in the limits -\infty and +\infty of the above mentioned variables q, \mu and h. The integral...
  13. Oxymoron

    Poisson PDF with non-integer support

    Homework Statement If X is a Poisson random variable with \lambda = 2 find the probability that X>0.5. Homework Equations The Poisson PDF: P(x,\lambda) = \frac{\lambda^k}{k!}e^{-\lambda} The Attempt at a Solution Usually with these sorts of probability problems where they ask...
  14. F

    Marginal PDF Bounds: Calculating Integration Limits

    Hey guys, So I'm having trouble telling what the integration bounds should be when calculation the marginal PDF of two random variables. So the joint PDF fX1,X2(x1,x2) is a constant C = 1 in the regions x1 and x2. The regions are bound by 0<=x1<=1 and 0<=x2<=2(1-x1). If the marginal PDFs are...
  15. N

    Marginal PDF Problem: Accidental Edit Fixed

    Oops, I accidentally edited over this post =( Thankfully it's quoted in the next one.
  16. S

    Performing Detection with IID RV: Unknown PDF & Neamen Pearson Test Efficiency

    Hi all 1) When we are performing detection , and we have received this y(n)=x(n)+z(n) for n=0,1,2,3..., where z is gaussian noise, but about x(n) we don't know its distribution , all we know that it is I.I.D. random variable with zero mean and fxed given variance. Now my question is can we...
  17. Q

    Finding the PDF of Y = X2 with Given E(X) and E(X2)

    Homework Statement random variable of X has pdf: f(x) = (3/16)*x2 from interval (-2,2). Also, E(X) = 0, and E(X2) = 12/5. Find the pdf of Y = X2 Homework Equations The Attempt at a Solution I don't really know where to start.
  18. E

    The PDF of the Square of Sum

    Hi, Suppose we have two random variables X and Y with CDFs and PDFs F_X(x), F_Y(y), f_X(x), and f_Y(y). Now suppose that a new random variable formed as Z=(X+Y)^2. How can we find the CDF F_Z(z) and the PDF f_Z(z) of this new random variable? Note: X and Y are independent random variables. Thanks
  19. PainterGuy

    Uploading of pdf pages of an ebook

    hey everyone, i have an ebook in pdf form and wanted some help with some of the portions there. online hosting services like flickr and imageshack don't allow uploading of pdf pages. while reading the book i can annotate, highlight etc. the only option I'm left with is to convert pdf pages to...
  20. A

    Mathematica Mathematica Export to PDF problem

    Hi guys, I have a problem with exporting to PDF format from Mathematica 7.0. As seen in the attachment PlotLabel is correctly displayed in the note book (test.nb), but when I try to export it, some characters just don't seem to be displayed correctly (plot.pdf). I've tried the "Save...
  21. M

    Integral involving normal pdf and cdf

    Suppose φ(x) and Φ(x) denote the familiar standard normal pdf and cdf. I am interested in an expression for the integral: S φ(ax+b) Φ(x) dx, from ZERO to INFINITY. Many thanks
  22. O

    Is there an analytical solution to the integral of a PDF?

    Hey all, I have an engineering background with a pretty terrible grounding in statistics and just about all maths that I can't immediately visualize as some kind of dynamic system, so forgive me if this is an obvious question! I am working through a set of derivations for a conditional...
  23. M

    Finding PDF of Link B for 2-Bar Linkage

    Any help is appreciated on this: This is the projection on the x-axis of a 2-bar linkage. I need to find the PDF of the end of the second link (point B) 1. Link C of length rC is pinned at the origin and its other end is pinned to link B at point C. Its length projected on the x-axis is...
  24. T

    Calculating P(X<0.5) and V(x) for r.v. X with pdf f(x) = ax + bx^2 0<x<1

    Question: The r.v. X has pdf f(x) = ax + bx^2 0<x<1 0 otherwise If E(x) = 0.6 , find i) P(X<0.5) ii) V(x) Solution: E(x) =0.6 = \mu Stuck here
  25. S

    Complex Integral to find pdf of user in CDMA system

    Hi everybody while trying to find the pdf of user in CDMA, I got stuck up with an integral, which is given below: \int_0^1\frac{1}{x (\ln x)^{\frac{n-1}{n}}\sqrt{y^2-x^2}}dx where y is a constant and n is an integer. Please help me to solve this integral.
  26. F

    Pdf of sum of two random variables problem

    Hi, everybody. My problem is about Probability and Random Process. i can't understand the probability density function of sum of two random variables and function of product of two random variables. Here is my question with a part of a solution: how can i find these problems solutions and...
  27. D

    Find the PDF of W when W= X + Y + Z. Random Varibles, Uniform Distrubutions.

    Homework Statement 1. Let X , Y and Z be independent random variables, uniformly distributed on the interval from 0 to 1. Use Theorem 3.8.1 twice to find the pdf of W = X + Y + Z . Thm. 3.8.1 States: If X & Y are continuous random varibles wth pdfs fx(x) and fy(y), respectively then...
  28. D

    Find the PDF of W = X + Y + Z on a Uniform Distribution

    I am stumped. I have that W=X+Y+Z and that S=X+Y These are all X, Y, & Z and Independent and Uniformly Distributed on (0,1) I found the pdf of S to be (Assume all these < rep. less than or equal to): S when 0<S<1 2-S when 0<S<1 So I continued: To do pdf of S+Z=W I figured...
  29. K

    Multiple Random Variables - find probability given joint pdf

    Homework Statement Show that the function defined by f(x,y,z,u) = 24*(1+x+y+z+u)^(-5) for x,y,z,u>0 and f=0 elsewhere is a joint density function. Find P(X>Y>Z>U) and P(X+Y+Z+U>=1). Homework Equations distribution function = quadruple integral from 0 to x (or y or z or u) here of the...
  30. P

    PDF of the sum of three continous uniform random variables

    Homework Statement X1, X2, X3 are three random variable with uniform distribution at [0 1]. Solve the PDF of Z=X1+X2+X3. Homework Equations The Attempt at a Solution PDF of Z, f_z=\int\intf_x1(z-x2-x3)*f_x2*f_x3 dx2 dx3 I saw the answer at http://eom.springer.de/U/u095240.htm, but I cannot...
  31. M

    PDF distribution of ln(x) when x has normal distribution

    Hi All, I'm wondering if ln(x) has any know distribution when x is a normal random variable? Also, is there any distribution for x that generate a known distribution for ln(x)? Thanks,
  32. S

    Finding the conditional pdf

    Hi, This is a homework problem that I'm having a very hard time with. We are given that f(x)=e^(-x) for X greater/equal to zero. The question is to find f(x|A) where A is the union of the events (1 less/equal x, and x greater than 10). I can't figure out how to go about doing this...I...
  33. C

    Understanding Joint PDF and Independence in Probability: Solving for P(X+Y<=2)

    Let the joint PDF of (X,Y) be of the form: f(x,y) = 1/8x(x-y), 0<=x<=2, |y|<=x f(x,y) = 0 elsewhere Find P(X+Y<=2). The answer that my teacher gave was P(X+Y<=2)=∫01dx ∫-xx 1/8x(x-y)dy + ∫12dx ∫-x2-x 1/8x(x-y)dy I do not understand how my teacher could separate the integral like...
  34. M

    Creating Histogram & PDF for Data Sample

    Hi All, I just need your small help in Matlab programming of histogram and PDF Task to create and reproduce histogram and Probability distribution function for a given data sample (Inter packet arrival times).please see the attachment for the data (TV_80_port_testing.dat) and...
  35. O

    Need assistance figuring out a model PDF

    please excuse any inaccuracies in the following formulation of my problem. here it goes: 1. there are n discrete time steps 2. between every time step, transitions 0 -> 1, 1-> 0 can happen between states denoted by 0 and 1. the two possible transition directions are poisson processes, i.e...
  36. F

    Is the Weibull Distribution Effective for β < 1 Despite Divergence at t=0?

    When the weibull shape parameter beta is <1, the pdf is divergent at t=0 due to negative exponent of beta -1. With such a divergent distribution is it meaningful to use Weibull for beta <1?
  37. L

    LaTeX Importing part of a PDF document into latex

    hi, there is a figure that i want to include in my latex document. The figure is in someones thesis and i want to have just that one figure in my latex document but I am not sure how to this. in power point i can just use the snap shop feature but how do i do it for latex where it requires a...
  38. M

    Plotting PDF for Inter Packet Arrival Times

    Hi Everyone, Iam new one to join the MATLAB .My task is to plot PDF for the given data from the .dat file I have three columns which contains as below like .The first column says port no , second and third is the inter packet arrival times of packet 1 and packet 2 . The whole data is huge...
  39. E

    Calculating Conditional Probability of Y with Exponential RVs

    Dear all, How can I find the the following conditional probability: f_Y(y/\gamma_f\leq \gamma_0), where Y=\gamma_f+\text{min}(\gamma_h,\gamma_g), where all gammas with subscripts f, g, h are i.i.d exponential random variables. Thanks in advance
  40. C

    Given Cont.Joint PDF function find Covariance MATRIX

    Hello Buddies, I need to calculate "covariance matrix" of the given joint PDF function. Joint PDF is fx(x1,x2,x3)=2/3(x1+x2+x3) over S (x1,x2,x3), 0<xi<1, i=1,2,3 How can I calculte the Covariance Matrix? Thanks
  41. O

    PDF of distance between measured coordinates with normally distr. errors

    hi, the problem i have is this: consider a line segment L of length d in R^3. the projection of the endpoints of L on a fixed plane can be determined with an error that is normally distributed, and the errors for the two endpoints needs not to be equal. Assuming that L is randomly oriented...
  42. U

    Pdf of area and circumference of a circle

    Homework Statement Suppose that the radius X of a circle is a random variable having the following p.d.f.: f(x)={ (1/8)(3x=1) for 0<x<2 0 otherwise Determine the p.d.f. of the area of the circle and the circumference of the circle. Homework Equations...
  43. E

    Finding PDF of uniform distribution

    Homework Statement Let X be a uniform random variable in the interval [0,1] i.e., X = U [(0,1)]. Then a new random variable Y is given by Y= g(X), where g(x)= -a. ln(x). Show that Y is exponentially distributed. What is the mean of Y? Homework Equations fX(x) = 1/ lambda . exp (-x/...
  44. G

    Fluids motion HARD. i attached the file as a PDF check picture from Q4

    Homework Statement µ Q.4 An incompressible fluid of density ρ flows steadily through a two-dimensional infinite row of fixed vanes, a few of which are shown below. The vane spacing is a. The velocities V1 and V2 and pressures p1 and p2 are all constant along their respective stations, (1) and...
  45. B

    Need Help Answering Astronomy Questions? Download the PDF!

    I have four questions that need to be answered. They are from my university course that I am taking in general astronomy 2. Could anybody tell me how I would obtain the detailed solutions to arrive at the answers? I have attached a pdf file of the questions and answers, please download it and...
  46. S

    Mathematica Simulating Normal Distribution in Mathematica: Histogram and PDF Plotting

    Hi guys, On my homework, I'm simulating a normal distribution on Mathematica by adding up a bunch of RandomReal[] , that is, uniform(0,1) random variables, and using the central limit theorem. I would like to plot both the histogram and the actual Gaussian probability density function on the...
  47. D

    Word to PDF: Convert Wrd to PDF w/ XP, Vista Compat.

    Hi I have a lot of work regarding documents management. I am looking for a word to PDF converter software compatible with Windows XP and Windows Vista as well which can even batch convert files. Please recommend some conversion tool. Any help is appreciated! Thanks!
  48. S

    Need some help with TENSION (problems 3 & 4 in the pdf)

    Homework Statement PROBLEM 3: A staging that weighs 290 N supports two painters, one 430 N and the other 490 N. The reading in the left scale is Fl = 500 N. What is the reading Fr in the right hand scale? Further description is the picture in the pdf. PROBLEM 4:So basically in problem 4, there...
  49. S

    The Marginal pdf of a Function

    Homework Statement The integral from 0 to infinity of xe^[-x(1+y)]dy Homework Equations The Attempt at a Solution I can't figure out why the answer would be zero to a pdf. Also, for the indefinite integral the calculator produces the answer xy*e^(-x-xy). I cant' figure out...
  50. R

    Using pdf to find the Probability of a range

    Homework Statement For a given cdf: Fy(y) = 0 for y less than 0 = y^2 for the range 0 to 1 = 1 for all values greater than or equal to 1 the problem asks to find P(1/2 < Y < 3/4) first using the cdf and then using the pdf...
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