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.
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...
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...
[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...
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...
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...
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?
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...
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...
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...
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...
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...
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...
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...
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...
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,∞)...
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...
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...
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...
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...
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??
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...
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...
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...
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
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...
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...
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?
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...
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...
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...
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...
“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...
"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"...
"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...
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...
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
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 =...
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.
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...
...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?
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...
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?
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...
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...