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. Q

    Why Does Electron Energy Have Negative Values?

    hi, why are the energy levels of electrons in say a hydrogen atom -13.6ev, -3.4 eV etc ? i thought energy is always positive? what does the negative mean? thanks!
  2. G

    Why do tensile testing graphs show a negative slope at these regions?

    Do tensile testing machines reduce the value of load in these regions? If yes, why? If no, what's happening in the graph?
  3. G

    Why negative times negative is positive

    hey friend can anybody give answer? why (-) * (-) = (+)
  4. P

    Electric potential equals the negative area under the graph

    When taking about potential and electric field, potential difference is equal to the negative of the area under the graph of E vs distance? why is that. My book defines it as the negative integral of Force times ds or V(intitial) - area under the curve. I don't understand why it's negative. I...
  5. E

    How Do You Calculate Final Velocity of a Projectile Fired at a Negative Angle?

    Homework Statement Trying to work out final velocity of a projectile that is initially fired at a negative angle. Initial velocity is 30m/s at a negative angle of 16 degrees. Initial height is 0.44m. Can't get my head around the initial horizontal velocity. I figure its Vox =30 sin 16...
  6. D

    Understanding Negative t Coordinates in Lorentz Transformations

    In lorentz transformation, why has t -sign
  7. A

    I can't find the log of a negative number

    Homework Statement there is an equation: 2^x=-6 Homework Equations The Attempt at a Solution I know that log need to be used to find x. but I can't find the log of a negative number,,
  8. P

    2 unit negative chargees and a positive charge +q are along the same

    2 unit negative chargees and a positive charge +q are along the same line. what should be the magnitude of charge q and in which position must it be placed so that the three charges remain in equilibrium...
  9. K

    What does negative resistivity mean

    silicon has a negative temperature coefficient of resistivity. So that means that it's resistivity decreases as temperature increases. How is that possible? Also, would that mean that at some certain temperature higher than room temp, silicon would act as superconductor? It has a very high...
  10. G

    Simple question about nth-roots of negative numbers

    I've been doing this online math bridging course from a German uni to which I am planning to go soon, it is going through all high school maths from the beginning(it has been a while since I did it). The chapter on roots so far ignores complex numbers, which will be introduced in a later...
  11. B

    Why do you Tack on The Negative For this Integral

    If you integrate 1/(1-y)dy why do you end up with a negative in front of your answer -ln|1-y|+c
  12. A

    Square root of negative complex exponential

    Homework Statement Solve \sqrt{-e^{(i2\pi)/3}} Homework Equations The Attempt at a Solution I seem to be missing something simple, as I take: \sqrt{-1} = i then, e^{(1/2)*(i2\pi)/3} which comes out as: ie^{i\pi/3} however, the solution is: -ie^{i\pi/3}, and I can't seem to see where...
  13. X

    Solving Work Negative Sign Homework Questions

    Homework Statement See attachment Homework Equations The Attempt at a Solution Why is it -umg(50)? Why negative? Also I think this has something to do with conservative force and friction, and I'm very confused on this. Any help would be appreciated thanks.
  14. 8

    Stats question regarding negative binomial

    Homework Statement The problem is attached in the pdf Homework Equations The Attempt at a Solution I have the solution, I just don't really understand it. In the solution, the author takes the expected value of the negative binomial ( n(1-pi)/pi ) and plugs it into the g'(x)...
  15. K

    Three negative point charges lie along a line

    Three negative point charges lie along a line as shown in the figure. figure: http://tinyurl.com/7xppvc8 Find the magnitude and direction of the electric field this combination of charges produces at point , which lies 6.00 from the charge measured perpendicular to the line connecting the...
  16. Fredrik

    F is integrable if and only if its positive and negative parts are

    Homework Statement Problem 2.6.3. in "Foundations of modern analysis", by Avner Friedman. Let f be a measurable function. Prove that f is integrable if and only if f+ and f- are integrable, or if and only if |f| is integrable. Homework Equations Friedman defines "integrable" like this: An...
  17. K

    Maximum initial speed the electron can have without hitting the negative plate

    Two parallel plates are 2.0 cm apart and the electric field strength between them is 1.0 × 10^4 N/C. An electron is launched at a 45 degree angle from the positive plate. What is the maximum initial speed v0 the electron can have without hitting the negative plate? i think the answer is...
  18. N

    Limits involving logs, negative inf and probabilities.

    Hello! I am playing around with an equation (i.e. it's not a textbook question), and I arrived at the following problem: The equation is: A = -1*\sum_{i=1}^{N}*\log_{N}(P_{i})*P_{i} Pi is less than or equal to 1 and more than or equal to 0, and is a probability of finding an object in a...
  19. E

    What Does Modulus of Negative Numbers Mean in DFT Symmetry?

    One of the discrete Fourier transform (DFT) properties (symmetry property) is that: x^*[-n]_N \stackrel{DFT}{\leftrightarrow}X^*[k] where * means conjugate, and [.]_N means modulus N. What is the meaning of modulus of negative numbers? Thanks in advance
  20. G

    Find potential difference of negative charged particle?

    Homework Statement The work done by an external force to move a -8.5μC charge from point A to point b is 15x10^-4 J. If the charge was started from rest and had 4.82x10^-4 J of kinetic energy when it reached point b, what must be the potential difference between a and b Homework Equations...
  21. T

    What defines a real negative voltage?

    This has been bugging me for a long time! Now if electrons are -Q and the V is basically what energy is added to that Q how do you define the voltage as being - or +. For example in a computer system, the data cable has + and - negative voltage, so is the polarity switch at ether end on the...
  22. N

    Do I Use the Binomial or the Negative Binomial?

    Homework Statement Two teams, A and B, play a series of games. If team A has probability .4 of winning each game, is it to its advantage to play the best three out of five games or the best four out of seven? Assume the outcomes of successive games are independent.Homework Equations...
  23. W

    Why there is no answer when negative value is being square root?

    why there is no answer when negative value is being square root? e.g: square root of -9 when i try to find answer from calculator, ''math error '' appears.. so is there an explanation for this question?? this question may looks so weird..but i m juz asking out of curiousity..
  24. N

    Non-sensical negative entropy? (grand canonical ensemble)

    Hello, I was investigating a system with N indistinguishable particles, each of which can have an energy \pm \epsilon, and using the grand canonical ensemble, i.e. \Xi = \sum_{N=0}^{\infty} e^{\beta \mu N} Z_N. But my entropy formula is S = \left( \textrm{a couple of $\sim N $ positive...
  25. T

    Why Do Negative Numbers Exist?

    Why did we define negative numbers? They don't exist in real life. Was their purpose to add negative numbers instead of subtracting positive numbers? Why can't we have more positive numbers that are twice as positive as regular positive numbers? Or numbers that are twice as negative as regular...
  26. Z

    Negative off-diagonal elements in density matrix?

    I have a quick question. I've been trying to search for an answer, but I'm probably looking in the wrong places. Is it valid to have negative off-diagonal elements in a density matrix? Thanks!
  27. K

    Can i do modulus on a TI-83? How can i compute a negative modulus?

    I am studying Integer Modulo in my Cryptography and Data Security class. We are dealing with mainly modulo 26 [the alphabet] right now. I understand if it is addition or multiplication you just take the remainder of the result divided by, let's say 26 in this circumstance. ie: (5+25)mod26 = 4...
  28. Y

    Motion sensorPositive or negative?

    Homework Statement 1 - A person moving toward the motion sensor with constant velocity.. 2 - A person moving away from the motion sensor with constant velocity.. Homework Equations For both statement above.. Is the velocity positive or negative? The Attempt at a Solution For...
  29. putongren

    Definition of Negative Pressure in the Stress-Energy Tensor

    I've been trying to find out what the definition of negative pressure in the context of General Relativity. There are some information on negative pressure and I found this: https://www.physicsforums.com/archive/index.php/t-299495.html The starter of that thread also doesn't know what the...
  30. F

    Negative Voltage/Current Readings in Induction Generator: Causes & Solutions

    Homework Statement I am taking the readings of voltage/current in a small induction generator; the readings are conveyed as negative on the voltage/current sensors on my data-logger, and positive on the multimeter in both areas. When the magnet passes through the coil, and power is generated...
  31. S

    Modulo division with negative power ?

    if f(x)modg(x) is valid(means , if it yield a remainder) then , can there be negative powers of x in f(x)? for example is (x-29)mod(x2 - 3) possible ? can we do modulo division like this or is it strictly defined only for positive powers of x?
  32. G

    Temperate a scalar than why negative temperature?

    What's the meaning of negative temperature if temperature can only be a scalar? Why the construction of negative temperature in degrees Fahrenheit?
  33. E

    Biot-Savart law My proof includes a negative sign

    Homework Statement A square coil of wire of side length 2a lies in the yz plane. A current I flows through the loop. The x-axis is defined such that it passes through the centre of the loop, with the loop boundaries being at z±a and y=±a respectively. Given that I flows in a direction...
  34. R

    Exploring Negative Resistance: Understanding its Effects on Electrical Current

    Lets see if I understand this one correctly. Basically negative resistance is when an object actively draws electrical current through it. The object almost encourages current to flow through it? Thanks AL
  35. S

    Estimation, negative binomial variable

    Hey, there's this thing I can't wrap my head around. Let's say we have a negative binomial variable x, with parameters p and r. That is, x is the number of failures we get before the rth sucess, while looking at random bernolli variables with sucsess rate p. It can be shown that...
  36. P

    Are only vectors capable of being negative in physics?

    I want to make the above claim in a physics paper for my intro to physics class, but first I want to confirm if it is absolutely correct. My reasoning goes that Force, acceleration, and velocity, can be negative, but mass and kinetic energy cannot be. Is my conjecture sound?
  37. P

    Proof that a negative mass causes superluminal speeds?

    I've heard this theory, based on the assumption that if negative mass objects exist, they would travel faster than light. I planned on mentioning this in a physics paper I have to write for my class, but I just realized that I have no idea what formula shows this correlation. Can somebody help...
  38. F

    What is the required impulse to bring the car to rest?

    Homework Statement A car with a mass of 1.0 X 103kilograms is moving with a speed of 1.4 X10 2m/s. The impulse required to bring the car to rest is? Homework Equations impulse = change in momentum... The Attempt at a Solution the answere is 1.4 X 105 N X S or is it the negative...
  39. S

    Why is the answer to this electricity question negative?

    A proton (m = 1.7 * 10–27 kg, q = +1.6 * 10–19 C) starts from rest at point A and has a speed of 40 km/s at point B. Only electric forces act on it during this motion. Determine the electric potential difference VB-VA. Here is what I did: V = \frac{U}{q} U = qV = \frac{1}{2}mv^2 V_B - V_A...
  40. P

    Can Logarithms Be Defined for Negative Numbers in Advanced Mathematics?

    I recently had a test (precalc) where we had to solve log(x)-log(x+4)=2 for x. The answer comes out negative. I understand that in precalc we are defining the logarithms for just positive numbers, but- Is it ever justified to define a logarithm for all numbers, both negative and...
  41. I_am_learning

    Multiple Choice Question negative marking

    You attend a multiple choice question exam, and you have n (say 10) questions whose answers you don't know at all. There are 4 choices in each question. A correct answer yeilds 1 marks. An incorrect answer has penalty of -0.25 marks. Is it wise to attempt all the questions in random? It...
  42. F

    Magnitude of vector, negative in part.

    This is actually not a full problem, just a part of one I'm having trouble with: Homework Statement If I have a acceleration vector, say [ bk^{2}e^{kt} - bc^{2}e^{kt} ]e_{r} + [ 2bkce^{kt} ] e_{θ}. How can I find its magnitude? Homework Equations Mag vector |a| = (a^2)^(1/2) The Attempt...
  43. W

    Negative Mass: Exploring the Possibilities

    I was thinking, can an object have negative mass? If an object with positive mass needs infinite energy to go at the speed of light, would an object with negative mass need infinitely negative energy (if negative mass were possible, this would be possible too right?) If an object had negative...
  44. S

    Multiplication of negative numbers

    Hello everyone I have trouble understanding the idea of multiplying two negative numbers. Why is product of such multiplication a positive number? Its so confusing.
  45. S

    Exploring Negative Signs in SHM Equations

    Hi all, I know that there are many ways to derive the equations for SHM. I'm clear on how the negative signs come out when we use derivatives; but I've a problem understanding how the negative signs come into play using the reference circle. 1. If the centripetal acceleration is a = rω2...
  46. K

    Can Up Quark Absorb Negative W Particle to Become Strange?

    Can an up quark absorb a negative W particle and become a strange quark? I know s can turn into u via the opposite process (emission of positive W), but can the interaction go the other way? This arises when trying to draw the Feynman diagram for the rather unlikely decay B^+\to...
  47. E

    Does antimatter (negative matter) have negative mass ?

    Does antimatter (negative matter) have "negative mass"? If not, why is this so suspected? And could anything theoretically have negative mass?
  48. A

    Dark energy <=> negative energy?

    Sorry if this sounds a bit mixed up. When I was growing up, in the late 1990's, popular science books about cosmology use to describe the average mass-energy density of the universe, especially comparing it to the critical density. Those books used to say that visible matter gives too-low...
  49. N

    A Damped Oscillator and Negative Damping Force

    A damped oscillator is described by the equation m(x'') + b(x') + kx = 0, where the damping force is given by F = -b(x'). Show that the rate of change of the total energy of the oscillator is equal to the (negative) rate at which the damping force dissipates energy.
  50. Y

    Hawking radiation and negative gravitational charge

    I was wondering if virtual anti particles had a postulated anti gravitational charge if that would be inconsistent with Hawking radiation as virtual anti particles would always be ejected from the vicinity of the Schwarzschild radius whereas virtual particles may or may not be ejected depending...
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