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. B

    How to remove background from a PDF file?

    I have a PDF file which has a weird dark yellowish background that renders it unreadable when printed in grayscale. I am not interested in the yellow background I just want black text from the PDF. I want to do this for a quite a large number of PDFs so I want a process that is either...
  2. B

    How to convert all pages of a pdf into A5?

    I have a PDF file in which different pages are of different size because I made it up from images of different sizes. For printing purpose I want all the pages to be of A5 size, How can I do that ? Sorry if this is silly but I have no experience in working with PDF, this is the first time I...
  3. C

    I Towards a matrix element definition of PDF

    In Schwartz's book, 'Quantum Field Theory and the Standard Model' P.696, he starts to derive an expression for a parton distribution function in terms of matrix elements evaluated on the lightcone. Most of the derivation is clear to me, except a couple of things at the start and midway. The...
  4. M

    LaTeX Embedded fonts from LaTex to PDF

    Hi PF! I am submitting a pdf and am generating it in LaTex, specifically I'm using TeXShop. Instructions on submission say: "Ensure that all fonts are embedded in the PDF file and that only Type 1 or TrueType fonts are used. In addition, any offeror who creates files using TeX or LaTeX is...
  5. L

    MHB Code language for editing PDF files

    I have around ~24 PDF files I want to edit. I want to delete the first page of each file OR scan for certain text in the file/delete the text (whichever implementation is easier). What would be the most convenient and straight forward coding language to do this with and what would be my starting...
  6. Saracen Rue

    Proving function f(x) is a PDf given integral relationships

    Homework Statement Prove that ##\int _0^a\left(\frac{f\left((sin(ln(c))x\right)+\sqrt{\cos \left(e-\pi ^2\right)}}{\ln \left(\pi ^2-e\right)+\pi ^2\sqrt{\cos \left(e-\pi ^2\right)}}\right)dx## is a probability density function (when ##a=\frac{1}{\pi ^2}##) given that ##\int _0^{\pi...
  7. F

    MHB Marginal PDF for Sum of Squares: Identifying Distribution and Calculation Method

    Let $$X_1,\dots,X_n$$ be i.i.d $$N(\mu,\sigma^2)$$. What is the marginal pdf of $$\sum_{i=1}^n (X_i-\overline{X})^2$$. I'm guessing it's some sort of chi square distribution but how to find this I am unsure. Thanks
  8. Saracen Rue

    A PDF formed from a multivariate function

    Homework Statement A probability density function, ##p\left(x\right)=\int _{-a}^a\left(f\left(x,\left(a-y\right)\right)-f\left(y,ax\right)\right)dy##, can be formed from the bivariate function ##f\left(x,y\right)=y\sqrt{\left(x-2\right)^2-y}## over the domain ##[0,b]## - where ##b## is the...
  9. sukalp

    Efficient Download of PDF from Teacher's Google Drive: A Guide

    hello i wanted to ask you that if we have a teacher website name. when we open pdf of his website it opens in google drive. when i opened c++ assignments file was zipping download is taking time but i am unable to download. what is the correct procedure for downloading pdf of google drive
  10. Saracen Rue

    Find the values of 'a' and 'b' for the following PDF

    Homework Statement A probability density function is defined by ##f\left(x\right)=\left|a\right|\left(x+1\right)-\left(ax-1\right)^2## where ##x∈[0,b]##. Determine the values of the constants ##a## and ##b##, given that the graph passes through the point ##(b,0)##. Homework Equations...
  11. woody stanford

    I Building a List of Feynman Diagrams

    Back again. This time I'm looking to build a small catalog of Feynman diagrams for my own use (and when I'm done to put it on the Internet in PDF format). I need your help to get a list of URLs together that I can download the required PDF's off the internet, bring them into Illustrator and have...
  12. Rectifier

    Looking for a software to highlight areas in PDF - Linux

    Hey there! I am looking for a free PDF viewer that is capable of highlighting areas and text and that is available for Debian (Linux). Thanks in advance.
  13. DiracPool

    How to Change Default PDF App in Chrome/Browser

    I've got this default PDF file opener in Windows 10 that drives me nuts. Every time I activate the cursor to navigate the page these banners drop in from the top and side and it's just irritating. I don't know how to change the default PDF app, though. I'd like to just change it so when I...
  14. A

    Relativity Free PDF download of Hawking & Ellis (1973)

    Where can I find a free digital copy of The Large Scale Structure of Space-time by Hawking and Ellis?
  15. E

    I Finding the PDF of X Given an Expression

    Hi. I have the following expression X=\frac{G\frac{x_1}{x_2}\gamma_Q}{\frac{1}{G}x_3 \gamma_P+1} where ##x_i## is an exponential random variable with mean 1. All other parameters are nonzero positive constants. Basically I want to find the probability density function (pdf) of ##X##. So I...
  16. E

    A Given the pdf of Z = X+Y, what's the pdf of X if X&Y are IID

    A common problem in statistics is, "Given that X is distributed according to the pdf f(x) and Y is distributed according to the pdf g(y), what is the pdf h(z) of Z = X + Y?" The answer is the convolution of f(x) and g(y): $$ h(z)=(f*g)(z)=\int_{-\infty}^\infty f(z-t)g(t) dt =...
  17. gracy

    What Happens to the Voltage Across a Capacitor When the Plates are Separated?

    A capacitor has a capacitance C and is charged using a battery. After disconnecting the battery the two plates are separated until they are twice as far apart as originally. What happens to the voltage across the capacitor? I think answer should be voltage increases . As battery has been...
  18. J

    Random process involving CDF and PDF of standard normal

    Homework Statement Let $$ \Phi(x)=\int_{-\infty}^{x} \frac{1} { \sqrt{2\pi} } e^{-y^2 /2} dy $$ and $$ \phi(x)=\Phi^\prime(x)=\frac{1} { \sqrt{2\pi} } e^{-x^2 /2} $$ be the standard normal (zero - mean and unit variance) cummulative probability distribution function and the standard normal...
  19. BobblyHats97

    If X ∼ Uniform(−1, 1) find the pdf of Y = |X|

    This question is killing me. I know the graph is non-monotonic so i have to split up finding F(Y) for -1<Y and Y<1 but then what do I do with the modulus? >.< Any help would be greatly appreciated! Thank you so much x
  20. W

    Conditional Expectation of Multiple Independent Random Varia

    Homework Statement Given X,Y,Z are 3 N(1,1) random variables, (1) Find E[ XY | Y + Z = 1] Homework EquationsThe Attempt at a Solution I'm honestly completely lost in statistics... I didn't quite grasp the intuitive aspect of expectation because my professor lives in the numbers side and...
  21. W

    Finding the PDF and CDF of a given function Z = X/Y

    Homework Statement Given a Uniform Distribution (0,1) and Z = X/Y Find F(z) and f(z) Homework EquationsThe Attempt at a Solution So I'm just trying to make sure i have the range correct on this one... I'm honestly lost from beginning to end with it. R(z) = {0,∞} because as y is very small, Z...
  22. W

    Calculating C and Marginal PDFs for a Uniform Distribution on a Bounded Area

    Homework Statement E = { (x,y) | |x| + |y| ≤ 1} fx,y (x,y) = { c (x,y) ∈ E 0 otherwise } Find C. Find the Marginal PDFs Find the conditional X given Y=y, where -1 ≤ y ≤ 1. Are X and Y independent. Homework Equations I'm taking a guess here in the solution... but F(x,y) = F(x)F(y) and...
  23. T

    The Joint PDF of Two Uniform Distributions

    Homework Statement A manufacturer has designed a process to produce pipes that are 10 feet long. The distribution of the pipe length, however, is actually Uniform on the interval 10 feet to 10.57 feet. Assume that the lengths of individual pipes produced by the process are independent. Let X...
  24. J

    How can I find the CDF and PDF of Y?

    Problem Let X be a uniform(0,1) random variable, and let Y=e^−X. Find the CDF of Y. Find the PDF of Y. Find EY. Relevant Equations http://puu.sh/kAVJ8/0f2b1e7b22.png My attempt at a solution If I solve for the range of y I get (1, 1/e), but because Y is not an increasing function, my...
  25. W

    Expectation of a function of a continuous random variable

    Homework Statement X ~ Uniform (0,1) Y = e-X Find FY (y) - or the CDF Find fY(y) - or the PDF Find E[Y] 2. Homework Equations E[Y] = E[e-X] = ∫0 , 1 e-xfx(x)dx FY(y) = P(Y < y) fY(y) = F'Y(y) The Attempt at a Solution FX(x) = { 0 for x<0 x for 0<x<1 1 for 1<x } fX(x) = { 1 for...
  26. T

    Histogram to PDF Conversion: Confirm Experimental Approximation

    Say I have a large data set of 1,000,000 points. If I plot a histogram of this data, I get a bar chart with bins along the x-axis and the number of items in each bin along the y-axis. If I take the number of items in each bin and divide this by the total number of items (1,000,000 in this...
  27. W

    Conditional PDF question -- I think anyway....

    Homework Statement Suppose you take a pass-fail test repeatedly. Let Sk be the event that you are successful in your kth try, and Fk be the event that you fail the test in your kth try. On your first try, you have a 50% chance of passing the test. P(S1)=1−P(F1)=1/2. Assume that as you take the...
  28. S

    PDF of open ended double dice rolls

    In many games a pair of standard six sided dice is used. I denote this 2d6. In this particular game, if a die is rolled the result is registered. If it returned a 6, it is re-rolled while a 5 is recorded. So it's basically a 2d5+1 open ended roll, which in theory could end up with very large...
  29. D

    Sketch and mathematically represent pdf of given signal

    Homework Statement I've been asked to sketch and mathematically represent the pdf of 2 signals: (a) rep2T{5 rect(t/T) - rect((t-T)/T)} (b) rep2T{2 rect(t/T) + 4Arect(2t/T)} A(t) is the lambda function A(t) = 1- t for 0 <= t <= 1 1+t for -1 <= t <= 0 Any help would be much...
  30. ChrisVer

    LaTeX Insert Latex PDF Figures: Easy Guide to Captions

    Hi, I have some figures in a pdf form, and I'd like to pass them into latex as figures ->meaning I want to be able to use a caption. I used the: \usepackage{pdfpages} but this inserts the pdf page as it is, and I can't "edit" it (by adding a caption). Is there any possible way to do it?
  31. A

    MHB Integral over gaussian pdf where parameters depend on integrand

    Hallo math helpers , i am trying to understand how one could solve the following integrall: $$\int_a^b \mathcal{N}(f(x_1,...,x_n,t),g(x_1,...,x_n,t)) dt$$, where $$\mathcal{N}$$ is the normal distribution, and $$f(x_1,...,x_n,t): \mathbb{R}^{n+1} \rightarrow \mathbb{R}$$, $$g(x_1,...,x_n,t)...
  32. Lewis7879

    Joint problem density function problem

    I need help guys I can't understand this Can anyone explain thoroughly how do I form the range for this question? f(x,y)= e-x for 0≤x≤y≤∞ 0 Otherwise Find P(x+y≤1) I attempted this by integrating through the range of 0≤y≤(1-x) and 0≤x≤∞ but that...
  33. _N3WTON_

    CDF and PDF Calculations

    Homework Statement The current in a certain circuit as measured by an ammeter is a continuous random variable X with the following probability density function: f(x) = 0.057x + 0.272 if 3 <= x <= 5. It is 0 otherwise. a) Verify that the total area under the density curve is 1. b) Obtain the...
  34. H

    MHB How to Solve a Truncated Lognormal PDF SDE?

    Hi, I'm trying to solve this SDE; the pdf of r is known (truncated lognormal) -\d{z}{t}=\frac{r^2}{\alpha}\cdot\frac{\beta z-\theta/r}{z} Please help me!
  35. F

    PDF of multimodal circular data

    Hi, I have a data vector that consists of directions measured in an experiment. I wish to create a probability density function. As the data is circular and multimodal I use a kernel density estimate with von Mises distribution (essentially a Gaussian on the unit circle) as the basis function. I...
  36. S

    How is E(X) = 1 obtained for this continuous joint pdf?

    Homework Statement The problem and its solution are attached in the TheProblemAndSolution.jpg file. Homework Equations E(X) = integral from -infinity to infinity of x * ##f_X(x)## ##f_X(x)## = integral from -infinity to infinity of ##f_{XY}(x,y)## dy The Attempt at a Solution Basically, how...
  37. T

    PDF of a continuous random variable

    Homework Statement Let X denote a continuous random variable with probability density function f(x) = kx3/15 for 1≤X≤2. Determine the value of the constant k. Homework Equations I'm not sure if this is right but I think ∫kx3/15 dx=1 with the parameters being between 2 and 1, The Attempt at a...
  38. A

    CDF to PDF problem (probability)

    Homework Statement Homework Equations integral from -inf to inf of fx(x)dx = 1, fx(x)=PMF The Attempt at a Solution I get values for probability function PMF of: 0.3, x=0 0.3, x=2 A-0.6, x=3 I guess I try to find area under curve of PMF which will be equal to 1. (0.3)(2) +...
  39. Q

    MHB Marginal probability density functions (pdf)

    I have a set of two related queries relating to marginal pdfs: i.How to proceed finding the marginal pdfs of two independent gamma distributions (X1 and X2) with parameters (α1,β) and (α2,β) respectively, given the transformation: Y1=X1/(X1+X2) and Y2=X1+X2. I am using the following gamma...
  40. B

    Finding the pdf and cdf of this function

    Homework Statement Let ##X## have the pdf ##f_X(x)=\dfrac{1}{\sqrt{2\pi\sigma^2}}e^{\dfrac{-(x-\mu)^2}{2\sigma^2}}## where ##-\infty<x<\infty,-\infty<\mu<\infty,\sigma>0##. Let ##Z=g(X)=\frac{X-\mu}{\sigma}##. Find the pdf and cdf of ##Z##[/B] Homework EquationsThe Attempt at a Solution...
  41. Y

    Why my pdf films turn into HTML when transfer?

    I am switching computers so I transfer some pdf files from the first computer(Win 8) into a memory stick. Then I transfer from the memory stick to the second computer( Win 7). But all the pdf files become Firefox HTML Documents. 1) When I copy from the first computer, I open the memory stick...
  42. D

    MATLAB Matlab estimate PDF from random variable X

    How do I estimate the pdf from a random variable \(X\) where \(X = U_1 - U_2\) and \(U_i\) are uniform random variables? In the code below, I used unifrnd(-5, 5, 1000, 1) which generated a 1000x1 vector of uniform random number between -5 and 5. How do I estimate the PDF for X? rng; X =...
  43. E

    LaTeX Creating a PDF Audio Presentation

    Hello all, I have created a PDF presentation using LateX. I want to add my commentary on the slides by recording my explanation using a mic and mark some parts of the slides while I am commenting, at least to be able to point where I want using the cursor. How can I do that? Thanks
  44. M

    How do I copy and paste equations from the textbook pdf to word

    How do I copy and paste equations from the textbook pdf to word? I just want to make my own notes. And make them as fast as possible.
  45. M

    Prove that the function given with f(x) is a PDF

    Hi, Could someone help me prove that the function given with ##f(x) = \binom{x-1}{r-1} p^{r}(1-p)^{x-r}## is a probability density function, where ## x= r, r+1,..., \infty ## and ## 0<p<1 ## I thought to solve it somehow by using the binomial theorem, but since it's the upper part...
  46. M

    Creating PDFs: A Guide to Converting Data into Histograms and Fitting Curves

    hey all (again)! how do people create pdf's? it seems like we start by collecting info and turning it into a histogram. then do we simply look at an array of curves, or is there something more, such as what is done of finding the least squares method for fitting data to a line? thanks!
  47. C

    Probability Functions and Distributions for Independent Series of Experiments

    Homework Statement Two independent series of experiments are performed. The probability of a positive result (independent of each other) in the respective series are given by p and q. Let X and Y be be the amount of experiments before the first negative result occur in the respective series...
  48. R

    What is the Expected Value of Two Random Variables with a Joint PDF?

    Homework Statement two random variables have a join pdf f(x,y)= c , x^2+y^2<= 1, x >0, y>0 0, otherwise Find c. Find E{xy}. Homework Equations The Attempt at a Solution For the first part, since area= pi/4, c(pi/4) = 1 c=(4/pi) b) x=cos θ y= sin θ ∫∫-(sin...
  49. G

    Unique wave function for a fixed gauge and a velocity and position PDF

    ¿Is there an unique wavefunction for a system if we know the distribution probability function for variables from the system and first derivatives from these variables and we have the gauge fixed (by external impositions not related with the wavefunction knowledge obviously? (Nothing about...
  50. stripes

    Finding the joint moment generating function given the joint PDF

    Homework Statement Homework Equations The Attempt at a Solution The problem is the integral is non-elementary, so now what? Part (b) follows trivially from part (a). But is there some kind of shortcut I have to take, because no matter what substitution I do, the integral...
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