Negative Definition and 1000 Threads

In mathematics, a negative number represents an opposite. In the real number system, a negative number is a number that is less than zero. Negative numbers are often used to represent the magnitude of a loss or deficiency. A debt that is owed may be thought of as a negative asset, a decrease in some quantity may be thought of as a negative increase. If a quantity, such as the charge on an electron, may have either of two opposite senses, then one may choose to distinguish between those senses—perhaps arbitrarily—as positive and negative. Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature. The laws of arithmetic for negative numbers ensure that the common-sense idea of an opposite is reflected in arithmetic. For example, −(−3) = 3 because the opposite of an opposite is the original value.
Negative numbers are usually written with a minus sign in front. For example, −3 represents a negative quantity with a magnitude of three, and is pronounced "minus three" or "negative three". To help tell the difference between a subtraction operation and a negative number, occasionally the negative sign is placed slightly higher than the minus sign (as a superscript). Conversely, a number that is greater than zero is called positive; zero is usually (but not always) thought of as neither positive nor negative. The positivity of a number may be emphasized by placing a plus sign before it, e.g. +3. In general, the negativity or positivity of a number is referred to as its sign.
Every real number other than zero is either positive or negative. The non-negative whole numbers are referred to as natural numbers (i.e., 0, 1, 2, 3...), while the positive and negative whole numbers (together with zero) are referred to as integers. (Some definitions of the natural numbers exclude zero.)
In bookkeeping, amounts owed are often represented by red numbers, or a number in parentheses, as an alternative notation to represent negative numbers.
Negative numbers appeared for the first time in history in the Nine Chapters on the Mathematical Art, which in its present form dates from the period of the Chinese Han Dynasty (202 BC – AD 220), but may well contain much older material. Liu Hui (c. 3rd century) established rules for adding and subtracting negative numbers. By the 7th century, Indian mathematicians such as Brahmagupta were describing the use of negative numbers. Islamic mathematicians further developed the rules of subtracting and multiplying negative numbers and solved problems with negative coefficients. Prior to the concept of negative numbers, mathematicians such as Diophantus considered negative solutions to problems "false" and equations requiring negative solutions were described as absurd. Western mathematicians like Leibniz (1646–1716) held that negative numbers were invalid, but still used them in calculations.

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  1. J

    Can negative dielectric possible

    can negative dielectric constant be possible?if yes then for which one.
  2. K

    Engineering Acquiring negative voltages in real life circuitry?

    Homework Statement I'm working on a project for my circuit analysis class in which we designed a circuit that involves a wheatstone bridge, takes the voltage difference and then amplifies it to a useable level. I am past that phase of the design, I have a working circuit for that on a...
  3. M

    AC Half Cycles: Positive vs Negative

    what does the positive and negative half cycles in an ac represent?
  4. X

    How come potential energy is negative when charges attract

    and positive when they repel? It doesn't make any sense to me at all. To what are they referring to? The way I see it, if you're got... +...- The closer they are, the less electrical potential energy they have. So it should still be positive. And if you've got two like charges C...C The...
  5. J

    Re-arranging equation: negative time for exponential

    [b]1. Homework Statement I have a sequence whereby 10000=100(1+e^(kt)+e^(2kt)+...+e^(39kt)) where k=-4.7947012×10^(-3) which was dervied from dy/dt=ky Re-arranging i get 99=1+e^(kt)+e^(2kt)+...+e^(39kt), letting e^(kt)=r I put it into the computer and i get 1.04216=r=e^-4.7947012×10^(-3)t...
  6. S

    What exactly does negative permittivity mean?

    Hi, this is my first time posting on these forums but I've been reading them for a while. I was having a look at metamaterials and it mentioned that metamaterials had negative permittivity and negative permeability. I also found that metals naturally had negative permittivity; though I am...
  7. X

    How do we know if an electric field is negative or positive?

    Homework Statement Note: this is actually my own question, not something from a book. So if I am wrong about some terminology please let me know In physics questions, they will tell you an electric field is |Some Value|. Since |Some Value| (lets call it X) is always positive, how do we know...
  8. A

    What happens to power when voltage is negative

    Hello, In the following voltage vs time graph as we can see the voltage becomes negative often time. My question is: if power= V*I then when voltage is negative do I have negative power?
  9. 1

    HELP Is my answer correct? Is negative Friction possible?

    HELP! Is my answer correct?? Is negative Friction possible?!? Homework Statement A dogsled team has four dogs that pull a person and a sled with a combined mass of 100 kg. A) They start from rest and reach a speed of 45 km/h in 2.5s. What is the average force applied by each dog? B) Suppose...
  10. J

    How to handle negative momentum

    We have a variable-inertia flywheel coupled by a shaft to a fixed inertia flywheel. The VIF (variable-inertia flywheel) has a moment of inertia range of 10 to 5 (m2*kg) and an initial velocity of 100 (rad/s). The fixed inertia flywheel (fw) has a MI (moment of inertia) of 10. The initial...
  11. K

    Combining Negative and Positive Feedback in an OpAmp: What Are the Effects?

    What happens if you combine both negative and positive feedback in one opAmp? assuming you only have unity gain in the negative configuration and no capacitors? I reckon adding capacitors would add some oscillatory behavior but would that be the case if both configurations are made only of...
  12. S

    Negative frequencies in spectrum analysis

    Negative frequencies in spectrum analysis... Hello everyone... When we do the frequency analysis of a signal using Fourier transform, we get spectrum at negative frequencies also. What are they and what is the physical significance of such frequencies? Its hard for me to imagine a negative...
  13. E

    Determining if a 3x3 matrix is negative semidefinite

    Homework Statement I have the matrix A = [-10 3.5 3; 3.5 -4 0.75; 3 0.75 -0.75] I need to determine whether this is negative semidefinite. Homework Equations The Attempt at a Solution 1st order principal minors: -10 -4 -0.75 2nd order principal minors: 2.75 -1.5...
  14. P

    Does relativity permit tachyons given that they have negative gamma?

    I've heard it said that relativity formally permits tachyons and that we don't believe they exist merely because there is no empirical evidence of them. However, since a tachyon's speed exceeds c, its γ must be imaginary. The t-component of the particle's 4-velocity is, depending on...
  15. R

    Associated Legendre polynomials for negative order

    Homework Statement I just need to deduce the expression for the associated Legendre polynomial P_{n}^{-m}(x) using the Rodrigues' formula Homework Equations Rodrigues formula reads P_{n}(x)=\frac{1}{2^{n}n!}\frac{d^n}{dx^n}(x^2-1)^n and knowing that...
  16. Z

    Photon with negative energy, Compton Scattering

    Hello PF people, Homework Statement In a Compton scattering event, after the collision, the Photon has an energy of 0.12 MeV and the Electron has an energy of 0.04 MeV. Find the following: i) The Wavelength of the photon before the collision. ii) The scattering angle for the photon...
  17. L

    Non negative Measurable function and Simple function

    Homework Statement Ω=ℝ A=σ({x}:x\in ℝ}) Determine H_{+}(Ω,A) and S_{+}(Ω,A) Homework Equations H_{+}(Ω,A) is the set of f:Ω→[0,∞) such that f is A/Borel(ℝ) measurable S_{+}(Ω,A) is the set of function in H_{+}(Ω,A) such that number of f(Ω) is finite and f(Ω) \subseteq [0,∞)...
  18. M

    Bernoulli principle - negative pressure

    I will write a program about principle bernoulli, but i have a problem. My input data: Pressure(p1) = 1000 Cross-section(A1) = 1 Velocity(V1) = 1 Cross-section(A2) = 0.5 Velocity(v2)= (V1A1)/A2 to simplify: h1=h2 i'm counting the pressure p2 : p2 = p1 + 0.5*v1*v1 - 0.5*v2*v2...
  19. J

    Negative Voltage: What Does It Mean?

    Ok, I am starting to understand what voltage is. But I'm sort of confused when it comes to negative voltage. I know that voltage is defined as potential energy per unit charge. I understand it as analogous to "pressure". I don't understand what it means to have negative voltage though. How can...
  20. C

    Can Negative Energy Be Produced in Small Amounts Through the Casimir Effect?

    At what amounts can negative energy be produced by the Casimir effect? I know these are very small, but I am curious to know how small.
  21. P

    Clausius inequality correct for negative temperature

    is clausius inequality correct for negative temperature?, if you see the proof of it in positive temperature its not correct.
  22. ShayanJ

    Interpretation of temperature for negative ones

    In statistical mechanics and kinetic theory,it is shown that temperature can be interpreted as a measure of the energy of particles.But such an interpretation seems to need refinement because of introduction of negative absolute temperatures. Can we still interpret temperature as a quantity...
  23. P

    Negative temperature and entropy

    we know the entropy in each process increases is it true for absolute negative temperature?
  24. W

    Work done by E field to move electron from negative plate to postive.

    The facing surfaces of two large parallel conducting plates separated by 10.0 cm have uniform surface charge densities that are equal in magnitude but opposite in sign. The difference in potential between the plates is 500 V. An electron is released from rest next to the negatively charged...
  25. K

    What's negative frequency in analysis of s domain and w domain

    what's negative frequency? can we say s=-3 in example bode plot ! or we can say it's unstable at w=-3 rad/s that's I mean is there negative frequency??
  26. C

    Electric Charge- why is the electron the negative

    Why wasn't the electron fixed with the 'positive' value? wouldn't that simplify a lot of issues with electronics problems, i mean, that way things wouldn't have to be all backwards. like, wherever the electrons go is becoming more negative, and whichever direction they are leaving is more...
  27. J

    News Negative Income Tax: A Progressive & Simple Proposal w/ Benefits for All

    I am making a proposal that the United State abandons its current tax code and adopts the Negative Income Tax as its federal tax model. For those who don't know the Negative Income Tax would annually tax every person at the same percentage and it would give a tax deduction/reimbursement of the...
  28. J

    Does negative potential energy reduce the effect of gravity?

    Hello, my question is in the context of modeling static neutron stars via the TOV equation. This is for a 20 week research project for my undergraduate degree. I am creating different equations of state to relate energy density to pressure, I have already used ideal fermi gas models, and now...
  29. A

    Hand contact with capacitor negative (excess of electrons) terminal only.

    Thank you for any help you are able to provide. I myself think that the electrons will flow to the human body and further drain the battery.
  30. D

    Exploring the Relationship between -ln(-∞) and ln(∞)

    For instance, say I have -ln(-∞) Does the negative sign on the natural log cancel with the negative sign on the infinity? Is this true? -ln(-∞) = ln(∞) Thank you -Drc
  31. J

    Ring of charge (half positive, half negative)

    Homework Statement Two half-rings of charge of opposite polarity are brought together at the origin (so that the rings create a full circle against the y- and z-axis. Each half-ring has a charge of magnitude Q and radius a. Derive the net electric field at point P, located on the +x axis a...
  32. ElijahRockers

    Finding R for Negative Pole Frequency Transfer Function

    Homework Statement I have a transfer function: H(jw) = RCjwz / (1+RCjwp) and I'm being asked to find R, if C = 47nF and the desired pole frequency is at 3.3kHz. what I'm confused about is that the pole frequency is supposed to make the denominator of the transfer function 0, but...
  33. C

    Should Vout be negative or positive?

    I attached the circuit. I did kirkoff's voltage law (assuming current goes clockwise): -15+5-10,000I-40000I=0 where I=current I=-2*10^-4 A V_out=40,000*-2*10^-4A = -8V The way V_out is shown, it should solve to be negative, correct?
  34. Y

    How can ellipticity angle be negative.

    In plane wave elliptical polarization, the book said if the Ellipticity angle is possitive, it is a Left Hand Circular polarization(LHC). If Ellipticity angle is negative, it is Right Hand Circular polarization(RHC). My question is how can Ellipticity angle be negative...
  35. D

    It doesn't make sense to get negative

    The speed of car A is 72.2 km/h while the speed of car B is 53 km/h. If car B is now 48 km ahead of car A, how much time is needed for car A to catch up with car B? car A let x = the current position of car A speed = 72.2 km/h time = x/72.2 hours car B let x + 48 = the current...
  36. B

    Quick question about negative declinations

    I am trying to find the sky position of asteroids so that I can observe them using a telescope. This site quotes the declination angle in hours and appears to range from 0 to -24. I have never heard of a declination angle more negative than -12 hours. What does this mean...
  37. anorlunda

    Both positive and negative curvature?

    What happens to the Reimann tensor at the event horizon of a black hole? Do some of the 24 components become zero or infinite? What happens to parallel transport of a vector on the surface of an event horizon that is different than on a surface outside the event horizon? I'm newly educated...
  38. julcab12

    Similarities of negative absolute temperature to dark energy?

    “The inverted Boltzmann distribution is the hallmark of negative absolute temperature; and this is what we have achieved,” says Ulrich Schneider. “Yet the gas is not colder than zero kelvin, but hotter,” as the physicist explains: “It is even hotter than at any positive temperature – the...
  39. S

    Negative Temperature Achieved

    "Negative Temperature" Achieved I was reading this article which says that scientists have recently achieved a "negative temperature" system, which apparently has a temperature which is "below absolute zero"...
  40. C

    Negative temperatures , BELOW 0 Kelvin?-Confirmation please

    "Negative temperatures", BELOW 0 Kelvin?--Confirmation please Someone shared this article with me: http://www.huffingtonpost.com/2013/01/04/absolute-zero-record-setting-negative-temperature_n_2404666.html ...And I've seen a couple others apparently referencing the same thing. If it's a...
  41. X

    Negative Kelvin temperature? (Recent Science paper)

    Chemistry student saying hi to everyone Just read http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146 about negative temperature. I knew I wouldn't understand a single sentence of the actual Science paper, but I took a look at the Science perspective (Lincoln D. Carr) but...
  42. O

    Evaluate lim e^x when x approaches zero from negative

    Homework Statement What is the limit of e^x when x approaches zero from negative side Homework Equations The Attempt at a Solution Taylor series? Then the answer is put all x= 0 , and the answer is 1, but why the question ask from negative side?? Thank you very much
  43. A

    Inverse 2D rotation with negative parameters

    Homework Statement Say we have a 2D rigid body transform, with parameters p = [ p_1,p_2,p_3] for rotation, x translation and y translation respectively. I'm using the transform to .. transform an image. Is there a way to have: For a point x , y : x',y' = transform(x,y,p) <=> x,y =...
  44. M

    [Basic question] What are negative numbers?

    What are negative numbers? Have you even seen a negative number of chickens? i haven't. The idea is merely an abstraction of subtraction. An abstract idea doesn't have to have any physical significance at all, even if the idea was derived from physical things.
  45. A

    What is negative frequency(fourier transform)

    in Fourier transforms of normal baseband sigal , spectral components are replicated on both +ve and -ve sides of frequency axis. i know that both -ve and +ve frequency components contribute to the total power of the signal but i don't know the physical significance of the -ve frequencies...
  46. J

    If the positive plate on a charged capacitor will pass current to the negative

    ...plate of a different capacitor, why won't the positive end of a battery (lets say AA) pass current to the negative plate of a different AA battery. Does it have something to do with the chemical reaction that happens inside the battery?
  47. S

    Negative & Positive Shear Factor

    My question relates to constructional geometry & matrices aren't to be involved in the solution because stated Math level is up to O Levels... The figure below shows shear with y=3 as invariant line & shear-factor of 3 My question is if you are provided the original polygon & asked to do shear...
  48. A

    Negative energy in the Schrödinger equation

    When my book deals with bound states and scattering states it puts: E<0 bound state, E>0 scattering state. What reference for the potential have been used for these?
  49. T

    Negative Work or Positive Work? and gravitational potential energy

    Hi! So, when we're calculating the potential energy of a mass in space we make it negative because we assign infinity as the reference point. Now, to find the potential energy of something I understand that we find the work that is done to it to move it from the reference point to another...
  50. S

    Effect of negative gravity on time

    Current theory of the big bang postulates that there was a very period when gravity reversed and the result was what we term the 'big bang'. Assuming this to be true, negative gravity would cause time to be a function of i. -- 1/2 A = D / (T x T) If A is negative then either D or T...
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