What is Focus: Definition and 201 Discussions

FOCUS is a fourth-generation programming language (4GL) computer programming language and development environment that is used to build database queries. Produced by Information Builders Inc., it was originally developed for data handling and analysis on the IBM mainframe. Subsequently versions for minicomputers and such as the VAX and other platforms were implemented. FOCUS was later extended to personal computers and (in 1997) to the World Wide Web: the WebFOCUS product.

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  1. S

    What is the other focus in an elliptical orbit?

    Hello. I've read in many books that the orbits of the planets of our Solar system are ellipses. With the one Focus as the Sun. Well, what is the other one? I mean every ellipse has two focuses...
  2. F

    Focus on courses or work with high school teachers

    I have my BA in physics and two years of graduate work at Auburn. I had an excellent experience there as a TA, but my own courses suffered. Quite a bit of my time was spent messing around in the intro lab. I am currently accepted at University of Alabama Huntsville to start up with their...
  3. P

    Why does looking through a traw improve the focus or resolution you see?

    When I curl my hand up and look through it, even though I have terrible eye sight I can read the title of a book on my shelf even though I can't if I'm not wearing my glasses. Why is this? I just had a lecture on SNOM, (Scanning Nearfield Optical Microscope), where the lecturer made a comparison...
  4. T

    Parabolic Equations Using Vertex & Focus

    Homework Statement Write the equation of the parabola described. Vertex: (2, 4) Focus: (2,6) Homework Equations (x-h)^2 = 4p(y-k) The Attempt at a Solution (x-2)^2 = 4(2)(y-4) x^2-4x+4 = 8y -32 Do I need to isolate one of the variables, or can I leave the equation like this?
  5. D

    Stargazing Help My telescope fell and now it won't focus

    It fell halfway over, denting my metal garbage can lid. The finderscope came off but I could easily reattach it. I can see light and blur now...what should I do?? I don't want to just open it up without knowing what I'm looking for. Thank you!
  6. A

    Prove how focus of a spherical mirror = Radius of curvature/2

    Prove how focus of a spherical mirror = Radius of curvature/2
  7. C

    Lens can focus the light to a smaller spot by ?

    Lens can focus the light to a smaller spot by ...?? I learn that increase of the beam size of the laser before coupling it to the fiber can increase the coupling efficiency of it. Can I know why is this so? Maybe the fiber is of very small diameter, and the focal lens in front of the...
  8. A

    Young Chemical Engineers needed for AIChE Focus Group

    Are you interested in earning $100 to share your opinions? We're looking for Chemical Engineers, age 22- 35 to participate in a 1 1/2 hour discussion. We will be hosting focus groups in Houston, Chicago, and Philadelphia, and we need members of AIChE as well as non-members. The...
  9. B

    Applying to REUs: What Should I Focus On?

    I'm currently applying to a few reu's and all of them ask for a personnel statement. Most ask for a statement of purpose (why i want to go to an reu) and my goals for the future. My question is what is exactly i should concentrate on. Should I concentrate on why i want to go reu's in general...
  10. M

    Focus on Pre-Calculus for Calculus Prep - MoePhysics

    Hello, Iam self-studying pre-calculus, I just wanted to know what topics should I be focusing on in Pre-Calculus so ican move on to and be fully prepared for Calculus that's all and thank you, MoePhysics
  11. TheFerruccio

    Focus of an ellipse vs. cone

    An ellipse is a conic section. If you construct an ellipse using a cone, does the axis of the cone cross through one of the foci of the ellipse? if so, how can this be shown mathematically? This is just purely out of curiosity.
  12. L

    Find the focus and directrix of the parabola

    Homework Statement find the focus and directrix of the parabola: (y+2)^2 = 16(x-1) Homework Equations (y-k)^2= 4a(x-h) focus: ( h+a,k) vertex: (h,k) The Attempt at a Solution k=-2,h=1,a=16/4=4!, vertex at (1,-2) focus ( 5,-2) does that mean that i solved the problem or do...
  13. K

    Optics - For what distance must we focus our eyes to see this image

    An object is placed 1m in front of a plane mirror. An observer stands 3m behind the object. For what distance must the observer focus his eyes in order to see the image of the object?
  14. E

    Estimated power of a motor needed for a ford focus

    How do I calculate the estimated power of a motor needed for a ford focus, engine size:1788cc, 4 cylinders??
  15. M

    How can I control or focus a magnetic field?

    After I discovered that someone had made a handheld tesla coil (http://www.rmcybernetics.com/projects/DIY_Devices/plasma-gun.htm), I started thinking about the possibilities. For example, would it be possible to use a magnetic field(s) to control and focus the energy that is being randomly...
  16. K

    Elliptic orbit from empty focus

    hello, I am solving a problem about the angular velocity in an elliptic keppler orbit as seen from the empty focus of the ellipse. Homework Statement Show that the angular motion of a keppler orbit as seen from the empty focus is uniform to first order in the eccentricit. The Attempt at a...
  17. N

    How to focus a beam of charged particles?

    I was discovering a way to focus a number of charged particles which has been accelerated by Van de Graff generator into a beam.I do tried to find ideas in uniform magnetic field,but it seems I can only focus the particles onto a point rather than a beam.So here I was asking whether there had...
  18. C

    What Are the Key Considerations for EMC in Designing Laboratory Equipment?

    Hi First i should apologies if this should have been posted in the homework sections but the three points that are automatically added to the post before writting doesn't really fit my question, so i decided to post it here. Then a little info about the situation might be in order. I'm...
  19. N

    Microscope to view sample in focus with a completely relaxed eye

    Homework Statement A microscope has a converging lens (eyepiece) with focal length of 2.50 cm mounted on one end of a tube of adjustable length. At the other end is another converging lens (objective) with a focal length of 1.00 cm. When you place the sample 1.30 cm from the objective, what...
  20. Ed Aboud

    Which Programming Language Should I Focus On?

    Hi all. This question has probably been asked before but I couldn't find it so. Over the past year I have dabbled with a few programming languages such as C,C++ and perl. My question is, which one should I really focus on and why? Thanks for any help.
  21. A

    What lens shape gives perfect focus?

    Assuming ray optics model is valid, what lens profile focuses light to a point? It must not be spherical, otherwise there would not be the term 'spherical abberation'.
  22. E

    Navigating Grad School App: Math vs. Physics Focus at School

    I am a second-year student and I go to a school with a not-so-strong theoretical physics department but a very strong math department. I am planning on going to grad school in theoretical physics. I will have completed the physics major at the end of this semester and I am deciding which...
  23. U

    Internship: Focus on Electrical or Systems Engineerin?

    Internship: Focus on Electrical or Systems Engineerin? Hi, I'm a junior EE major. I've had an internship last summer as a manufacturing engineering intern and I'll have one more summer left (between my Jr and Sr year) until I graduate. When finding internships for this summer, should I solely...
  24. N

    How to focus for long periods?

    I've just been sitting here at my desk for the last three hours, and I realized that I have gotten about 1/2 hour worth of work done. I just keep getting distracted by things. Do any of you have any good techniques for focusing on things (assignments/studying/research) for long periods of...
  25. Saladsamurai

    Distance from one focus to the other

    Am I making this out to be too simple? I am given: The Sun's center is at one focus of Earth's orbit, how far from this focus is the other focus in meters and in terms of the solar radius? eccentricity=.0167 semimajor axis=a=1.5*10^11 meters. solar radius=R=6.96 *10^8 meters Now if c is the...
  26. E

    Is Primary Focus Magnification the Same as Focal Distance Equivalent in Optics?

    Primary focus magnification? Hello all: My name is Miguel, from Buenos Aires. I have a question... is it right in formal optics to name "magnification" the below formula or "focal distance equivalent" of a camera attached in primary focus (without telescope ocular and camera objetive, of...
  27. P

    Finding Distance Between Focus & Vertex of Parabola

    How do you find the value of the distance between the focus and vertix for the parabola given by the equation 6x^2 + 8 = 2y.
  28. M

    Focus moonlight wth a mirror system

    Well, I'm new in town and I have a serious problem. Read the story and then tell me if its possible: In a open spot of a forest, a kid sees a sparkle from a 150 meters Manson's window. The house is located 5 meters above the forest floor level and the open spot 1-2 meters from the floor...
  29. F

    Electrical Engineering - choosing a focus

    I am a junior in electrical engineering, and I'm at the point where I need to start choosing my technical electives (my focus courses). I took my first Electrodynamics course this semester. I friggen' loved the material. I thought it was VERY interesting although quite hard. I'm thinking about...
  30. C

    Where is the principle focus of a plain mirror?

    where is the principle focus of a plain mirror?
  31. N

    Taken adderall in order to study better or focus more on a test?

    Has anyone here ever taken adderall in order to study better or focus more on a test?
  32. R

    Question on light intensity at the focus of a lens.

    From using a magnifying lens under the Sun, I gather it can focus all or most of the light impinging on its surface area to a small spot and that is how it is able to create a greater intensity light at its focus (disregarding absorption in the lens.) Correct? What portion of the total light...
  33. F

    Programs EE Major - what math should I focus on?

    I just changed my major to EE (actually last semester). I was previously a comp sci major. While in CS I took calc I, II, discrete math, then calc III and linear algebra. I hated math when I took up to discrete math. I always just wanted to solve the problems on the computer. It wasn't until...
  34. K

    Find the vertex, focus, and the directrix of the parabola

    Find the vertex, focus, and the directrix of the parabola. I get tripped up sometimes, but I know how to find all of the stuff with an equation like this : (x+1)^2 +8(y+3) = 0 But how do I find it with equations like this y^2=-6x or x+y^2=0 Can you complete the square with...
  35. U

    Focus Axial Ray: Can It Pass Through Glass?

    is it possible to focus an axial ray through a double plano piece of glass placed in air? i don't think so because the glass will not reflect the ray towards the optical axis for the ray to focus in. is this thinking correct?
  36. I

    Same focus for all circular lenses?

    In school physics i have learned that the focus for a circular convex(converging) lens is f=r/2 where r is the radius and f is focus. But wouldn't a pair of identical lens made of a different material eg glass and perspecs which have different refractive indexes have different point of focus?
  37. zoobyshoe

    Focus, Attention, And Mental Filters

    Since I got interested enough in Neanderthal man to start reading about him, and because this leads to questions about whether or not modern man could have bred with Neanderthal, I have found myself getting into the habit of constantly checking out the slope of the foreheads of every person I...
  38. T

    Parabola with Focus (-5,0) & Vertex (-5,-4): Find Equation

    Fins an equation for the parabola with focus at (-5,0) and vertex at (-5,-4). I have come up with: x^2 + 10x + 16y + 89 = 0 How far off am I?
  39. D

    What Is the Equation of a Parabola with Vertex (-2, 3) and Focus (0, 3)?

    vertex (-2, 3), focus (0,3) Find the equation of the parabola. Dirac.
  40. S

    What is the estimated mass of a 20MW focus fusion reactor?

    Could someone please give me a rough estimate as to what the mass of a 20MW focus fusion reactor might be, please. Seamo
  41. O

    Photographing a Bird: Solve for Camera Lens Focus

    Hi! I am having trouble with this question: You are trying to photograph a bird sitting on a tree branch, but a tall hedge is blocking your view. However, as the drawing shows, a plane mirror reflects light from the bird into your camera. If x = 4.3 m and y = 4.5 m in the drawing, for what...
  42. G

    One Day to Prepare for E&M Midterm: What to Focus On?

    So i have a midterm tomorrow in E&M and I'm not well prepared at all. The whole class is pretty much already prepared to fail... so I'm not alone in that at least. Basically, i have one more day (tomorrow) to study, so i best make the best of it. We get to bring index card "cheat sheets" that...
  43. A

    Parabola equation with focus and directrix

    Hi, I need to determine the equation of a parabola given the focus (2,3) and the directrix y=-1 I sketched out a parabola opening up wards with a vertex of (1,1) I made two distance equations one for any point on the parabola to the focus, and one distance from the directrix to any point...
  44. A

    Find the equation of ellipse given vertices and focus Check

    Find the equation of ellipse given vertices and focus Check please Hi the question is find the equation of the following ellipse, given vertices at (8,3) and (-4,3) and one focus at (6,3) Well I drew a digram with the 3 points First I found the midpoint of the given vertices to get the...
  45. A

    Is Plasma Focus Fusion on the Verge of Success?

    I found this. Is it cranks or for real? http://www.progressiveengineer.com/PEWebBackissues2002/PEWeb%2028%20Jul%2002-2/28editor.htm http://www.focusfusion.org/
  46. M

    Focus in work deeply needed help

    Hello, Not to belong: i was good at school, and focussing on classes wad not a question for me, i was not studying too much every day, but i was able to focus many hours on studying on the exams night... The Problem is i lived in the middle east for the most in my life, and since i was...
  47. T

    Focus on School: Not Letting Video Games Get the Best of Me

    or getting it. I am but I'll be damned if I let it destroy my focus on school. In part that's probably why Halo 2 and Chessmaster are the only games I will be playing the rest of this year and far into 2k5 maybe. Sad really when a video game is threatening to take my focus. What happened to...
  48. D

    Unraveling Auto Focus: Cameras and Math

    hello, i am not sure that this is the correct forum to post in, but i am confident that the moderators can swiftly correct my error if that is the case. I was wondering a little about cameras and their auto foucs. How does it work and what is the math behind it?
  49. Ivan Seeking

    Bush's space vision loses focus

    http://www.nature.com/news/2004/040719/full/040719-19.html
  50. N

    What is the definiton of focus?

    what is the definiton of focus?if i put a converging lens or diverging lens in water,will the focus change? do you guys have msn? i have one.
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