Intro Definition and 563 Threads

  1. D

    Good rigorous intro combinatorics textbook?

    Hey guys, I'm thinking of self studying some math this summer, and combinatorics is one field I never really got into but want to learn a bit of. I rigorous proof experience from reading other books/taking rigorous classes, so I wanted to start off with something relatively rigorous. Thanks
  2. K

    Intro Electromag Question - Wave Equation

    Homework Statement Homework Equations The Attempt at a Solution b) I could figure it out if kz was changed to kx... Double Derivative of E(r, t) with respect to x is = 0 Double Derivative of E(r, t) with respect to t is = -ω2*E0*cos(kz - wt + ∅0) Multiply the second term by k2/ω2...
  3. D

    Suggestion on intro texts to read

    Hello everyone, I'm in my sophomore year of undergrad and I've recently started to do some work for an experimental particle physicist at my university. Right now he's really into neutrino oscillations (MINOS collaboration member) and neutrinoless double beta decay (NEMO3/SuperNEMO...
  4. M

    Intro physics - how many exercises do you do?

    Intro physics - seeking some help/opinions I'm studying for some upcoming exams. I feel like I've been able to grasp the material but at the same time, there's this voice in my head which keeps nagging me because I haven't done every question the book (and some more from other books). At some...
  5. R

    Skier Going Uphill - Intro Physics Problem

    Homework Statement You've skied down a slope and are going 20m/s when you hit the base of a slope that is 30 degree incline.? Assuming friction and drag are negligible, how much altitude (y) will you gain as you’re slowing down? How far up the 30 degree slope (∆x along the incline) will...
  6. K

    Are Calculus and Linear Algebra prerequisites for Intro to Mathematical Proof?

    Hi, all Going to take the Intro to mathematical proof class this coming quarter. It says the prerequisite is Cal III and linear algebra. I have taken those prereq years ago and forgot most of the materials. I don't know if the Intro to mathematical proof class has a lot of materials from...
  7. B

    Intro to Analysis (Boundedness of Cauchy)

    Homework Statement Prove the Boundedness Theorem for Cauchy Sequences by a contrapositive argument. Homework Equations The Attempt at a Solution If {an} is not bounded then {an} is not a cauchy sequence. We will prove that {an} is not a cauchy sequence by showing that there...
  8. B

    Is {yn} a Cauchy Sequence if {xn} Is?

    Homework Statement Prove the following assertion: Suppose {xn} and {yn} are Cauchy sequences of real number. If {xn} is a cauchy sequence and for every η>0 there exists a pos. int. N such that for every n>N so that abs(xn-yn)<η then {yn} is a Cauchy sequence. Homework Equations None...
  9. N

    Intro Statistics combination/probability problems.

    Hello. Am I counting right with these problems? I can't remember exactly how they were worded, but I remember what they were asking... 1) Given 20 men and 20 women, how many groups of 12 can you make with 6 men and 6 women. I said 20.Combination.6 * 20.Combination.6. 2) given S= {1, 2...
  10. J

    Ready to Connect with Medical Professionals and Discover Technical Advances?

    I am here to network with other medical professionals and learn about technical advances.
  11. B

    Intro to Abstract Math Question about divison of integers.

    (1)Assume a, b and n are nonzero integers. Prove that n is divisible by ab if and only if n is divisible by a and n is divisible by b.I'm wrong and can't remember why. I spoke to the professor about it for ~ 1 minute so it seems to have slipped my mind, it was because in one case it's true and...
  12. M

    Schools Should Calc I be the intro math course in colleges?

    I've observed that mathematics at college starts with Calculus I. Another observation of mine was that the math content in the majority of high schools is somewhat lacking and as such, jumping straight into a proper college calculus course might be a bad move. I know I'm not speaking for I alone...
  13. N

    Intro Statistics/ Probability help?

    Homework Statement 1) A computer firm presently has bids out on three projects. Let Ai = {awarded project i} for i = 1,2,3. Suppose that P(A1) = 0.20, P(A2) = 0.25, P(A3) = 0.28, P(A1∩A2) = 0.10, P(A1∩A3) = 0.06, P(A2∩A3) = 0.08, and P(A1∩A2∩A3) = 0.01. Compute the following...
  14. H

    How to Derive Displacement Current and Energy Density in a Capacitor?

    Homework Statement Show that the displacement current density which flows when a parallel plate capacitor gets charged is ε(dE/dt) where ε is the permittivity of the medium between the capacitor. What is the energy density stored in the capacitor and the force per unit area (pressure) on the...
  15. K

    Projectile Motion Homework: Finding Initial Speed and Flight Time

    Homework Statement A bullet is shot straight up into the air. It reaches a maximum height at h = 612 m. Find an expression for the initial speed of the ball. Using your previous results find a numeric time for the total flight time, t until the ball reaches the ground. Homework...
  16. L

    Something's wrong in < Intro to QM >, by Griffiths

    Hi, I am Liu, a undergraduate in mainland China, I post out this idea and want to see how you gentleman think, here it is: Griffiths says, in his book < Introduction to Quantum Mechanics >, if an insect fly in a path perpendicular to the direction in which lightbeam goes, the velocity of...
  17. W

    Divisibility in the Integers. Intro to Analysis

    Homework Statement Prove: If a|b and b|c then a|c. Assume a, b and c are integers. Homework Equations none The Attempt at a Solution If a divides b then that means that there is a real integer "r" that is ra=b . and since we assume b divides c then c=bs. After...
  18. A

    Help with Intro Programming: Debugging Errors

    hey I am doing a intro programming class and I am running into some problems. would really appreciate some help to see where I went wrong. Been trying to figure it out for hours now. Someone please help me out These are my errors c: In function ‘main’: c:33:9: error: expected identifier or...
  19. C

    Book recommendation on intro into fourier analysis

    I'm starting my first math class that involves Fourier analysis. The book we are using is Boyce and Diprima's Elementary Differential Equations and Boundary Value Problems. I find the examples helpful but I have a hard time grasping the conceptual sections. Any recommendations for good intro...
  20. G

    What do I need to know to learn intro to PDEs?

    Hi everybody. I need to take a course this spring called "intro to partial differential equations, Fourier series, and boundary value problems", and I'm wondering, how much vector calculus (if any) should I learn before this course starts? I have multivariable calculus and ODEs down just fine...
  21. D

    Number theory or intro to topology for comp sci/math

    I'm pursuing dual degrees in mathematics and computer science with a concentration in scientific computing and am trying to decide whether I should take intro to topology or number theory. Interests in no order are computational complexity, P=NP?, physics engines, graphics engines...
  22. N

    Are all material generally covered in Intro to Physics I?

    My professors skipped both chapter 11 & 12, Equilibrium & Elasticity and Fluid Mechanics. I'm worried that I will need to know these chapters for later classes or for the GRE. Has your professor skipped material in your class?
  23. S

    Momentum Operator question - Proof found in Intro to Griffiths QM

    Hi all I am trying to go through the Griffiths Intro to QM book and I'm afraid I'm already stumped! He determines the momentum operator by beginning with the following equation: <x>=\int_{-\infty}^\infty {x|\psi(x)|^2} He takes the time derivative and manipulates the integral: (I'm...
  24. C

    Intro to Algebra, Symmetric group # of elements of order 4 in S6

    Homework Statement How many elements of order 4 are in S6? (symmetric group with order 6) Homework Equations The Attempt at a Solution So, the different forms of elements with order 4 in S6 are (abcd)(ef), (abcd) from there I am sunk on how to calculate. I know there are...
  25. G

    Help me understand a homework solution - intro to ring theory - ideals

    Help me understand a homework solution -- intro to ring theory -- ideals problem: solution: The first paragraph is just saying the ideals generated by the units in the ring is the whole ring correct? Also, the principal ideals generated by 2, 4 and 8 are all the same correct? So...
  26. N

    Intro to complex analysis problems.

    1) How do you integrate 1/ [z^2] over the unit circle? After you integrate, do you put it in polar form or do you replace z with x + iy then solve it? I keep getting zero. It should exist since z=o is undefined, right? 2) How do you integrate x dz over gamma, when gamma is the...
  27. R

    Intro to Proofs: Greatest Common Divisors

    Homework Statement (a) Let a and b be integers with gcd(a,b)=d, and assume that ma+nb=d for integers m and n. Show that the solutions in Z to xa+yb=d are exactly x=m+k(b/d), y=n-k(a/d) where k∈Z. (b) Let a and b be integers with gcd(a,b)=d. Show that the equation xa+yb=c...
  28. X

    Programs Taking intro Mechanics 2nd semester freshmen year as a physics major?

    In my college students who don't have AP credit for calc I are required to delay physics a semester till they are done with calc I. Because of this students take E@M sophomore year and have to take a intro waves and thermo class 2nd semester sophomore year. This means students don't take...
  29. A

    Intro Analysis: Proof that a limit = 0

    This is an intro to analysis problem. I have already finished this proof (see attachment). I would like someone to check it for me. Its really short and easy. Thanks! -Abraham Tags: -Cauchy series -Infinite series -Limits
  30. nukeman

    Comp Sci Need help with C++ samples. Basic intro stuff. Thanks

    Homework Statement I am getting ready for a midterm, and I got a list of stuff to study for the exam. Since I was put into the class late, I missed some intro stuff. Can some of you, whom probably know some good resources, give me a link or show me a sample code of the following: ...
  31. M

    Intro to Logic: Answers to Your Questions

    I want A book which gives an introduction to logic , so it answer my questions like that I have posted https://www.physicsforums.com/showthread.php?t=541777 THanks
  32. A

    Preparing for Intro PDEs: What Topics from Calc III Are Essential?

    Hey everyone, I'm taking intro ODEs right now, and am taking intro PDEs next semester. I would like to know what i should review from calc III for this course. I took calc III over the summer at a community college and didn't learn very much, if I'm being honest with myself. I think I am...
  33. S

    Intro To Electrodynamics, Griffiths #1.9, me TRANSFORMATION LAW QUESTION

    I would just like to start off by saying the problem comes from Intro to electrodynamics, 3rd edition, griffiths. the problem is number 1.9. Question: Find the transformation matrix R that descries a rotation by 120 degrees about an axis from the origin through the point (1,1,1) the...
  34. J

    Intro Quantum Course Fourier Analysis

    Homework Statement Using ultra-short laser pulses, it is possible to probe the reaction dynamics of many chemical reactions, such as A+BC->(ABC)*->AB+C. This worksheet estimates some of the parameters necessary to do this. (a) If the energy available to each final states species is roughly...
  35. D

    Intro to Real Analysis: Supremum

    Homework Statement Find the supremum of E=(0,1) Homework Equations The Attempt at a Solution By definition of open interval, x<1 for all x in E. So 1 is an upper bound. Let M be any upper bound. We must show 1<=M. Can I just say that any upper bound of M must be greater than or...
  36. L

    Intro Matlab Q, floating point system

    Homework Statement So this should probably be easy, but for some reason I just can't seem to understand matlab, AT ALL. Anywho, Consider a normalized floating point number system with b=2 p=3 L=-2 and U=2 , plot all the numbers in this system in a horizontal line, and observe... lalala...
  37. D

    Proving a < b for All Positive Epsilon in Real Analysis

    Homework Statement If a < b-\epsilon for all \epsilon >0, then a<0 Homework Equations All I really have are the field axioms of the real numbers and the order axioms (trichotomoy, transitive, additive property, multiplication property). The Attempt at a Solution Well I broke this...
  38. L

    What is the significance of using a number like 2x10-10 in Intro Physics?

    I'm not quite sure where to start with this. Thank you in advance
  39. S

    How Do You Calculate Acceleration and Time in Kinematics?

    An object moving with constant acceleration has ve- locity v = 55.8 m/s when it is at x = 5.5 m and v = 100.4 m/s when it is at x = 10.5 m. What is its acceleration? How much time does it take for the particle to accel- erate from 55.8 m/s to 100.4 m/s? How fast will the particle be...
  40. S

    Intro Physics Question: Avoiding Collision on NY State Thruway at 106.8 km/hr

    You are driving along the New York State Thruway in a line of cars all traveling at a constant speed of 106.8 km/hr. The car in front of you applies its brakes for maximum accelera- tion. You then apply your brakes to achieve the same maximum acceleration after only a 1 s delay due to...
  41. S

    Intro to Topology Recommended Texts

    I know there are some threads out there already, but none really help me (see my description below). I am a high school student. My highest level of math education is Calculus I. I am currently taking Calculus II (although I already know the integration portion of this course). I have no...
  42. K

    What sparked my love for physics and science?

    Well, I've been on these forums for some time, and I've posted over thirty times, so I figure now is a good time to introduce myself. I'm going into eighth grade, (yeah, I know, I'm one of the youngest on the forums) and I've always had a massive curiosity about what makes things happen, and...
  43. K

    Galois Theory Intro Cut Short - Seeking Resources

    I was taking a lecture series this summer at my school where a professor was introducing us to introductory Galois theory. It was a very 'slack' introduction, without too much rigour. However, about a month in (only 3-4, 3 hr lectures) they stopped due to outstanding circumstances. I was a...
  44. A

    Prerequisite knowledge for intro thermodyanmics

    Hello I'm taking my first ME course in thermodynamics this fall (two or so weeks away), and was just a little curious if these intro courses are generally self-contained, or if the brief introduction to thermo found in physics I will play a pivotal role (or mechanics, as a whole)... edit...
  45. G

    Path Integral QM: Intro and Forward/Backward Scattering

    hello I started to read ‘QFT in a Nutshell’ by A. Zee. In the introduction to the path integral formulation of quantum mechanics there is the story about a particle going through a series of screens with holes drilled through them. Then the number of holes in each screen is increased. This...
  46. E

    Applicability of Intro To Algebra and Intro to Real Analysis to Physics

    Applicability of "Intro To Algebra" and "Intro to Real Analysis" to Physics Well, due to timetable complications I'm having to search for courses that aren't apart of my graduation requirements so I'm thinking about taking some math courses. Which one of these courses do you think is more...
  47. M

    Need an intro measure theory book

    Can anyone recommend a book(s) that covers these topics: Measure theory / lebesgue integration Hilbert Spaces Distributions PDE's The only material I have is the lecture notes and they are quite difficult to work through. I need to get the basics I think, before I will...
  48. M

    Best Resources to Relearn Introductory Chemistry?

    I took the first part of the college-level introductory chemistry classes (it's CHEM 1211 here). I took it a long time ago - 2002. When I took it, I didn't pay attention, it's a miracle I passed the class at all. And now I need the second part of the class. I'm worried that I'll be missing...
  49. C

    Intro Thermodynamics Question using Steam Tables

    Homework Statement A transparent rigid container is filled with 2 gallons of water. Initially the pressure is measured to be 10.2 psig, using a gage attached to the container. The local atmospheric pressure is 14.8 psia. It is observed that the liquid water in the container occupies two...
  50. M

    How Do You Calculate the Initial Speed and Angle of a Projectile?

    Homework Statement During a testing program, a photograph of the path of a projectile is taken, and subsequent measurements are added to the photo (See my attachment below .) Use the information shown in the figure to find a) the initial speed of the projectile b) the angle at which...
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