In mathematics, a coefficient is a multiplicative factor in some term of a polynomial, a series, or any expression; it is usually a number, but may be any expression (including variables such as a, b and c). When variables appear in the coefficients, they are often called parameters, and must be clearly distinguished from those representing other variables in an expression.
For example,
2
x
2
−
x
+
3
{\displaystyle 2x^{2}-x+3}
, has the real coefficients 2, -1, and 3 respectively, and
a
x
2
+
b
x
+
c
{\displaystyle ax^{2}+bx+c}
, has coefficient parameters a, b, and c respectively assuming x is the variable of the equation.
The constant coefficient is the coefficient not attached to variables in an expression. For example, the constant coefficients of the expressions above are the real coefficient 3 and the parameter represented by c.
Similarly, the coefficient attached to the highest multiplicity of the variable in a polynomial is referred to as the leading coefficient. For example in the expressions above, the leading coefficients are 2 and the parameter represented by a.
The binomial coefficients occur in the expanded form of
(
x
+
y
)
n
{\displaystyle (x+y)^{n}}
, and are tabulated in Pascal's triangle.
Homework Statement
This an example from Boyce+DiPrima's text on ODEs. Original problem is to solve 2t2y''+3ty'-y=0, given that y1=1/t is a solution.
But I'm stuck at the part where I'm to solve
2tv''-v'=0,
v being the second unknown solution.
The Attempt at a Solution
In the text...
Homework Statement
A 100 N force directed 37° below the horizontal is applied to a 30 kg object on a horizontal surface. If the magnitude of the acceleration of the object is 1.3 m/s2, what is the coefficient of kinetic friction (μk) between the object and the surface?
Homework Equations...
Homework Statement
Determine its 13^{th} Taylor coefficient of the Taylor Series generated by f at x = 3.
f(x)=e^(7x)
Homework Equations
I used the fact that the series for e^x was ∑x^n/n!
The Attempt at a Solution
Using that above, and replacing x with 7x, shouldn't my answer...
Homework Statement
F(x)=7x
Determine the 13th taylor coefficient of the taylor series generated by f at x=3
Homework Equations
Well, it looks like I just had to take the derivative, but by the time it gets to the 13th derivative, wouldn't the answer just be zero?
The Attempt at a...
Homework Statement
A body is fired from point P and strikes at Q inside a smooth circular wall as shown in figure. It rebounds to point S (diametrically opposite to P). The coefficient of restitution will be:
(Ans: ##\tan^2\alpha##)
Homework Equations
The Attempt at a Solution...
Hey! :o
"Let the polynomials
$$f(x)=1+\sum_{k=1}^{8}{(2k)x^{2k}} \text{ and } g(x)=1+ \sum_{k=1}^{8}{(3k)x^{3k}}$$
of $\mathbb{Q}$. Without calculating $f(x)g(x)$, find the coefficient of $x^{21}$ at $f(x)g(x)$."
Let's consider $f(x)=\sum_{k=0}^{\infty}{a_kx^k}$ and...
If we have a constant coefficient second order homogeneous ODE, the way to solve this is to suppose a solution of the exponential type. This yields a second order polynomial equation (the "characteristic equation") that the exponent must satisfy. In case the solutions of the characteristic...
"A hockey puck is hit on a frozen lake and starts moving with a speed of 12 m/s. Exactly 5.0 s later, its speed is 6.0 m/s. What's the puck's average acceleration? What is the coefficient of kinetic friction between the puck and the ice?"
I've calculated the acceleration, but I'm stuck when it...
Homework Statement
Why is the correlation coefficient between -1 and +1?
Homework Equations
we know correlation coefficient
\rho = \frac{E[xy]-E[x]E[y]}{\sqrt{\sigma_{x} \sigma_{y}}}
OR
r = \frac{\sum ^n _{i=1}(X_i - \bar{X})(Y_i - \bar{Y})}{\sqrt{\sum ^n _{i=1}(X_i -...
Hi all,
I am trying to calculate the damping coefficient of a linear viscous dashpot/damper given the dimensions of the piston, and the dynamic viscosity of the damping fluid.
I have found this calculator, but does anyone know the equation that it uses...
Suppose in the reaction 2 NO + O2 --------> 2NO2
Why when the the concentration of NO is doubled, the rate increases 4 times, I know that the rate is directly proportional to the square of NO concentration (I don't know why) and it's order of reaction is 2 ( I don't why ). but I still can't...
Homework Statement
A box rest on an incline making a 34 angle with the horizontal. It is found that a parallel force to the incline of at least 235 N can prevent the box from sliding down the incline. If the weight of the box is 800 N, find the coefficient of static friction between the...
Homework Statement
I wish to determine whether a SINGLE instrument provides reliable measures (test-retest reliability). This single instrument is not random (it's the only one available), and I will take 10 measurements for each individual that is part of a control group (and then again for...
Are there any theories or thoughts that view spacetime as 'having' a coefficient of thermal expansion... analogous to the CTE of water? An inflection with density in regards to temperature?
On this site I found how to calculate Cd and Crr coefficient from experimantal data:
http://www.instructables.com/id/Measure-the-drag-coefficient-of-your-car/
I am trying to implement it in a web page and in a smartphone application, so I must "replace" Excel Solver by an algorithm, but I'm...
1. a 5.0 kg block is pushed up a wall by a 90N force. Assume that the block starts from rest and that it has an acceleration of 0.5m/s^2.
a. find the coefficient of kinetic friction between the block and the wall.
b. Find the work done by each force acting on the block.
c. Find the...
Homework Statement
Two conductors are separated by an insulator. Model the insulator as a square barrier of height 0.01 keV and a width of 5nm. Determine the transmission coefficients for electrons of 7,000 meV.
The only thing is I have to use the approximation formula for finding the...
I have an example problem in my book. I have uploaded an image. The part I can't figure out is how to do the last part of the problem to come up with the transmission coefficient. The book gives me a formula but when I plug in all the numbers from the formula into my calculator I get a...
Homework Statement
A 30kg sled is sliding on a frictionless sheet of ice at a velocity of 4m/s. The sled encounters a rough patch of ice and begins to slow down. After traveling on the rough patch of ice for 3m, the sled's velocity is 2m/s. Determine the coefficient of friction between the...
1. Homework Statement and the attempt at the solution
Alright, here is a picture of the problem along with my solution:
My solutions gives the correct answer but the only part I don't understand is why the heat transfer coefficients are the same. If the two rods are made of different...
Homework Statement
Hi, i have a little problem with a demostration, I hope you can help me.
Homework Equations
this said that we have a system, a gas is containing in a recipe, there's no heat exchange neither work with the enviroment, only an expansion v to 2v, we have to find that...
1. a worker can supply a maximum pull of 150 lb on a cart w/c has a handle set at an angle of 40° above the horizontal. what is the coefficient of friction if he can just move a total load of 1500 lb ?
2. μ = Ff/mg
3. so i solved it by 150sin(40) divide by 1500cos(40), but I'm not...
Homework Statement
Two men loading a 900 kg piano onto a truck lose control and the piano slips, rolling down the loading ramp. The ramp is a 12 degree incline that is 3.2m long. If the piano accelerates down the ramp at 0.4m/s^2, find the coefficient of rolling friction.
Homework...
Please could somebody explain how the coefficient of static friction can be quoted as a constant in tables etc?
\mu_s = F_s/ R
In most cases the reaction force is constant but as I push the box harder the friction force increases.
Is \mu_s actually the coefficient of limiting friction? Or...
Hello, I am new to Aerodynamics and am having trouble understanding what exactly the roll damping derivative is.
The roll damping derivative is a measure of the change in rolling moment coefficient with respect to nondimensional roll rate and is usually negative.
Does that mean a glider...
Homework Statement
A crate of bananas has an initial speed of 4.2 m/s2. It slides across a floor, traveling 6.0m before coming to a stop. Find the coefficient of kinetic friction between the crate and the floor.
Homework Equations
Fnet=ma
v2=v02+2aΔx
The Attempt at a Solution...
Homework Statement
You are building a device for monitoring ultracold environments. Because the device will be used in environments where its temperature will change by 211°C in 2.99s, it must have the ability to withstand thermal shock (rapid temperature changes). The volume of the device is...
Homework Statement
When the temperature of liquid mercury increases by one degree Celsius (or one kelvin), its volume increases by one part in 550,000. The fractional increase in volume per unit change in temperature (when the pressure is held fixed) is called the thermal expansion coefficient...
Hi
Is the drag coefficient for a particular object the same in different mediums? Say we have Cd = 1 in air for one object, is Cd the same for this object in water?
Hello Fellow Forum,
How would you calculate the coefficient of friction for sandpaper? I'm testing mechanical resistance of a bioplastic, and I'm going to attach the bioplastic to different weights, and then rub sandpaper over the bioplastics. The one that breaks will be used to find...
This question relates to rate constants of transition events. The transmission coefficient κ reduces the value of the rate constant compared to the transition state theory (TST) value. I understand κ to be defined as the probability that a reaction coordinate q will proceed to product given that...
I have a bunch of noisy data points (x,y), and I want to model the data as y = ax2 + bx + c + noise where noise can probably be assumed to be Gaussian, or perhaps uniformly distributed. My data is firmly inside of an interval and I'm only interested in modeling correctly inside of this...
What is the minimum force needed to overcome static friction on a block whose normal force is 5.2N and has a coefficient of static friction 0.34?
A desk is pushed with a constant velocity along a floor. If the mass of the desk is 25kg,and the force required to keep the desk moving is...
A 20 Kg. mass slides up on an infinitely long inclined plane (that forms an angle of 30º with the horizontal) with a velocity of 12 m/s. It's known that the mass returns to the starting point with a velocity of 6 m/s. Find,μ, the coefficient of friction between the plane and the body.
This is...
It is well known that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure.
It must appointed that...
Homework Statement
Measurements of XRay scattering from a metal are made. The bragg peaks are θ = 53° and 48° for temperatures of 300K and 1272K.
What is the linear expansion coefficient?
Homework Equations
linear expansion coef is given by (1/L)(dL/dT)
Bragg equation (differential...
Homework Statement
Suppose you receive calls that follow a Poisson process model Y(t).
There are two hypotheses, Hypothesis1: E[Y(t)] = λ1t = 71t and Hypothesis 2: E[Y(t)] = λ2t = 74t. Let t = 30 the number of calls be 2175.
Find and compute a significance level α such that both...
Homework Statement
Does Coefficient of Performance for refrigeration cycle depend on refrigerant used? In reference to vapor-compression cycle
Homework Equations
COP = \frac{1}{\frac{T_{H}}{T_{L}}-1}
The Attempt at a Solution
I am split in my answer to this question.
I...
I am working on a motorcycle dynamics problem. I have written the equations of motion in matrix form in MATLAB (and mathcad). It is a 4 degree of freedom system, so I have a mass, damping and stiffness matrix all 4X4. I am able to find from these matrices the natural frequencies, and damping...
In a recent lecture,I learned that the friction coefficient "mu" between the tire and road surface is determined experimentally by using a graph. i.e a graph between the longitudinal tire force and the longitudinal slip. Well,how did engineers emperically arrive at such a graph in the first...
Homework Statement
I'm trying to derive the coefficient matrix (a) of a parabolically terminated cubic spline. This is the matrix of coefficients ##a_i \rightarrow a_n## where n is the number of data points provided.
With this matrix you can find all the other coefficients (b and c) that...
As you can see, around Reynolds number of 5 105 the transition occurs for a smooth sphere.
However, why is it that after this transition that the drag coefficient increases at turbulence?
1.
A 4.0 m long bar is suppotred by a string as shown in Figure 10-61. What must be the coefficient of friction between the bar and the floor if the bar is on the verge of slipping
Image:
2.
τ = r*F*sinθ or τ = r*F, where the force is perpendicular to the radius. Summation of...
Homework Statement
I know the diameter is 30 m and the radius is 15
The period for one revolution I suppose is some multiple of 7.03
Homework Equations
The Attempt at a Solution
I couldn't think of an equation where friction was involved where rotational motion was concerned. I...
Hello,
I was reading somewhere about how to control Rudders in RC planes. The basic equation here is the drag equation: F=0.5*ρ*v^2*C*A (take ρ=1Kg/m3)
where v is the velocity, C is the Drag coefficient of the control surface (Rudder in this case) and A is the area.
I am wondering if we have...